tens of thousands have taken to the streets of venezuela in rival mass rallies. the head of the opposition, juan guaido, is trying to force president maduro from power. the president also spoke at a rally in support of his leadership and the current government. russia has announced it is pulling out of a cold war arms control —— european countries say they will recognise juan guaido if —— european countries say they will recognisejuan guaido if new elections were not called by sunday. if new elections are not called by sunday. russia has announced it is pulling out of a cold war arms control treaty, and says it will develop a new hypersonic missile. it follows a move to withdraw from the treaty by the united states on friday. the governor of the us state of virginia, ralph northam, has refused to resign after he was accused of being in a racist photo in his yearbook. he says the person in the photo is not him. now on bbc news, it's time for click. this week: barriers without walls.

can tech trump the border? how microsoft came back from the dead. and the magic behind the avengers. the construction of a wall at the us—mexican border has dominated american politics since donald trump joined the presidential race back in 2015. we are going to build a great border wall to stop illegal immigration! it reached its crescendo in december, when the now—president announced a federal government shutdown over its funding. we're going to have a shutdown. there's nothing we can do about that. a record 35 days later it was finally lifted, without any real resolution, and it could easily be back on within weeks. as trump tweeted out a new design for his wall — now made of steel rather than concrete — the democrats did offer a potential compromise —

to fund a border which used technology rather than physical barriers. but is that feasible, and what would it look like? we sent nick kwek to arizona to investigate. so i'm on my way to the nogales border patrol station, one of the most technologically advanced control centres on the us—mexico border. the checkpoint itself processes hundreds of thousands of people every month. but today, i'm going on a ride—along with agent dan hernandez of border patrol, whose job it is to keep out those attempting to cross illegally. hey, just be advised i'm going to be around your location. we have 262 linear miles of border fence with mexico, but thousands of miles on the north end on the american side. it's a daunting task and it's very vast, but with the technology,

we're able to get a leg up on our adversaries. dan's patrol zone is larger than the state of newjersey. his sector of duty, tucson, made almost 40,000 arrests in 2017. out in this unforgiving terrain, field agents like him go about their daily patrol. every piece of technology used by them is vital and has to be reliable, even down to their radio coms. this one does have an encryption that's even higher level than most police departments, because of the national security concerns, because of the criminal element. you have a radio that is equipped with gps. so if something should happen, i become incapacitated, i could press that button and help will come. help will come from here, the nogales control centre, where officers can literally see what is going on, thanks to a newly updated surveillance system. their solar—powered integrated fixed towers, also known as ifts,

have long—range video and thermal imaging cameras, coupled with radar, to provide high—altitude points of view, with watchful eyes back at base. we do have tracking systems that can detect movement and it places the camera at the source of the movement. before, we'd see some pixelation. the cameras, just by the remote nature of their placement, it was very difficult to focus far away. but with technology, we've increased the amount of distances we can see and the accuracy of the images, i mean, we're seeing really crisp, sharp images. so we're able to identify things that come over the fence, people that come over the fence, contraband that comes over the fence, and not only that, but it increases safety. if i go out to an area and i don't know what i'm waiting on, and i don't know what's out there, and i run into an assailant with a firearm, it might be a bad situation.

but if i know that prior to going in there, i might be able to bring other resources with me. as well as saving agents‘ time, and potentially saving them, the ifts have helped secure areas where physical barriers are not. down near mariposa wash, fencing has been raised to prevent erosion from waterflow, but a person could easily walk through here. for all intents and purposes, we consider this defence the wall. so we don't want to think this is the only thing keeping america safe. we have the fencing as a tool, as another system we can utilise, but it by no means is supposed to keep anybody in or out. we are the force, with the agents, in conjunction with the technology, and this being utilised as a tool, that seamless integration of all three components is what makes the border secure, is having the agents to make an arrest, the wall, and then the technology to supplement both. this could be just a couple of miles, or it could be a couple of hundred yards. five minutes down the road,

dan shows me a border section where technology is already having to do most of the work in keeping people out. just looking at this, this is completely not what i was expecting to see, i guess, when people have visions of the wall or, you know, the mexican border, the us—mexico border. like i said, the presence of the fence isn't here. it's not a very powerful fence, by any means. it's just meant to keep vehicles out. whilst these sticks won't stop determined individuals, i'm told scattered sensors buried in the ground all around the area could catch them off guard. technology is intended to help agents do their duties. but, of course, it is not always criminals that get caught in the net. the recent migrant caravan crisis highlighted how many families make the perilousjourney in hope for a better life in the us. many have been torn apart, and some children have died since being detained by authorities. for dan, he says he is just doing hisjob. no matter on what side

of the spectrum you fall on, border security is important for the entire country. we're law enforcement officers. we don't dictate the law, we just enforce the laws, so the best way to enforce the laws is by doing it in the most effective and most efficient way. in 2017, border patrol seized over 890,000 pounds, or 400,000 kilos, of smuggled drugs across the us—mexico divide. drug mules, they try to camouflage themselves into the natural environment, so a lot of times you may not be able to see them. but our cameras can detect body heat and infrared technology allows us to see them in the middle of the dark night. so our technology is usually one step above the criminal element. as well as giving agents eyes—on from a long range of rural terrain, imposing structures like them have also been used to mitigate crime

in urban areas. nogales is a city divided in two. 0n the us side — 20,000 residents. 0n the other — 210,000. so up that hill there is a rvss tower, or remote video surveillance system, which is keeping a close eye across this area, which historically has been quite dangerous. but having that eye in the sky has helped improve safety — or so i thought. on top of that tin roof there. yes, those are rocks. yes, those are all rocks thrown at agents. 0k, we got to get out of here. yeah, you got to go, you got to go, you got to go. so actually — we actuallyjust heard a rock land on the top of that garage there, so obviously people up there are throwing stones at us. so we're heading out. come on. no—one is hurt, everybody‘s — code 4.

just be advised it's for safety. this is an area where usually scouts or people involved in human smuggling are perched, and i believe there's one person underneath that tree. so he's a human smuggler scout. how does that feel, knowing there is a guy who is watching you? it's a constant. they're up there all the time. you get more and more used to it. while scouts may sit for hours at a time, people crossing the desert move from place to place, so border patrol have mobile surveillance trucks to reach remote areas. they're equipped with thermal rangefinders, enabling operators to measure the distance between themselves and people crossing, and laser pointers, to give agents in the field wearing night vision goggles a heads—up. 0ne multiple surveillance capability truck can do the work of six people, orfour people. customs and border protection has also begun testing drones with facial recognition cameras to help monitor the border from an even higher vantage point, and border patrol is trialling a new mobile—based navigation tool

so agents can keep track of each other‘s live whereabouts. the border is changing every single day and technology or investment in technology allows us to keep up with the trends, with the smugglers, with counteracting any kind of negative action towards the united states at the border. whilst trump's wall continues to be a bone of contention, maintaining the border stretches beyond simply erecting more steel fencing. as i have come to learn, communication tools and surveillance systems play a pivotal role in everyday operations. whether technology can replace a wall altogether here is something which will be debated in the coming weeks. hello and welcome to the week in tech. it was the week that samsung announced a giant, 1 terabyte internal storage chip for smartphones. apple acknowledged the flaw in its facetime software which allowed eavesdropping.

and the usjustice department filed criminal charges against chinese company huawei and its chief financial officer. the company and its cfo deny the charges, which include bank fraud, obstruction ofjustice and theft of technology. the facebook research app paid 13 to 35—year—olds for almost complete access to their smartphones. the app is now no longer available on apple's app store. apple will now only let companies release apps through the app store. previously, the social network could let people install apps without going through apple. meanwhile, mit has made an inflatable pills to monitor the interior of your stomach. the sensor inside the ingestible tablet can potentially monitor problems inside the tummy for up to 30 days. it rapidly absorbs water once inside the body, and to deflate, patients simply drink a calcium solution to shrink the jelly—like pill back to a size which can go...out the other end. one more robot story for you from the italian institute of technology.

it has unveiled a soft robot which mimics plant tendrils. the plastic tube stretches when electricity passes through it and coils when the voltage is removed. researchers hope it could eventually help develop wearable devices that can change shape. cool so i get the jazzy bright yellow headphones. i'm in seattle with amos miller and his guide dog, trevor, and i'm about to try soundscape, a navigation app that uses no visuals, just 3—d sounds. ok, so i'm hearing voices. woman: the 0verlake transit center is 200m that way. as i turn around, the phone adjusts the stereo sound so that the speech

appears to keep coming from the correct direction. having it in 3—d space in that way makes it really effortless to know where things are. you don't have to do calculations in your head, and engage with them. you can just hear where it is. yeah. this 3—d audio is called dynamic binaural sound, and we're now going to use it to find our way to our destination. now, instead of giving you step—by—step instructions, the way that soundscape works is it will place an audio beacon, a virtual audio beacon, on the destination. so you can hear where it is, and we can decide how to get there. woman: beacon, 210 metres. i am hearing it. which side are you hearing? and it really is quite instinctive — just head in the rough direction that the sound is coming from. i think it's in this direction here. 0k. so do we just walk in the direction? yes. so now, we use our analytical skills to pay attention to what's around us. right, we don'tjust walk into that tree there. we don't walk into that tree. 0k. trevor, my dog, is pretty

good at avoiding trees. so shall we go? i don't know, dogs and trees, they kind of — you know. what is incredible, if you have never tried dynamic binaural sound, is that as i turn my head around, the trapping stays in the direction —— is that as i turn my head around, the tapping stays in the direction it should be coming from. i'm sorry, trevor, i overshot. this is augmented reality in audio and it's a really great idea. the sound is instinctive and unobtrusive which means we can have a chat without stopping and listening to spoken instructions. steps. right, three steps, here we go. one, two, three. beacon, 20m. find the doll, boy. he's arrived. that is, in the true sense of the word, that is a beacon. an audio beacon that we've just followed, as if someone was calling us. exactly. wow. so, you may be asking, whose headquarters am i at? which cheeky start—up has

come up with this idea? remember these guys? yes, microsoft. go on, admit it. you thought they were so last century, didn't you? paul allen and bill gates‘s company defined an era with their all—conquering windows operating system for pcs. but now we all use google and apple phones, which have left microsoft way behind. microsoft are, by the time the iphone and other smartphones came along, was very complacent. they had this really successful software business with office and windows, they also had the xbox, and it really couldn't manoeuvre the way a smaller, more focused company kind of could. i think you get an established business doing one thing, you put all your efforts into doing that one thing, and then you struggle to manoeuvre or anticipate the new technology that is coming along, and that may disrupt you.

about 25 years ago, they were on top of the technology industry, and now where are they? it turns out they are back on top of the technology industry. yeah, never mind apple, forget google and facebook — at the end of november 2018, microsoft became the most valuable company in the world for the first time since 2002. so where did it all go right? well, i'd say about here. five years ago, satya nadella became the boss and he was able to turn this super tanker around. i think the ceo of any company sets the tone, sets the direction. steve clayton is microsoft's chief storyteller, realjob title,

and he's well versed in explaining microsoft's resurgence, that's seen its value more than triple since nadella took over. where this guy caught the wave of personal computing, and this guy missed the wave of portable computing, this guy was determined to catch the next big one — cloud computing. because it turns out it's not devices that are mobile, it's people that are mobile, and what the cloud has allowed us to do is to put software anywhere, on any device. nadella seemed to accept that to move with the times, the company was going to have to do what it did in the beginning and be guided, at least in part, by the youngsters. let me show you a demo of the hypezone. young employees like lenin hsivalingam, whose passion for games streaming led him to win the company's fourth internal hackathon in 2017. so our idea was very simple, right? they are going to run computers on these live streams, understand them pixel by pixel,

and find interesting moments and show them to people. the result is the hype zone. it means that fans of the most popular games in the world, for example fortnite, mean they can use microsoft's games streaming site, mixer, to find the best battles. the game is kind of boring during the start game, and it gets really, really interesting during the endgame, when there are only two or three players left, so we try to use this technology to identify these super exciting end games. and any microsoft employee with an idea can come to this space, the garage, to hack, to build, and to work on new ideas. and is there anywhere cooler than a garage? well, yes, that'll be the batcave. and i'm looking at a visualisation of global earthquakes over the last 50 years or so. microsoft changed the way we worked once with windows,

and here is one possible workspace of the future. using its augmented reality headset, hololens, this is a glimpsejust of how our computing workspace may one day be all of our physical space. so today, we havejoining us, some of my team—mates. peter andjinna. jinna's in new york. jinna in new york, hi. and then there's peter. from san francisco! spencer, how's it going? and they can see us as well. this is spatial, a prototype environment where people can appear to be in the same room, and share the same images, videos and even 3—d models. so you have a big model of mars here. oh my goodness. amazing though this is, it might seem a bit too futuristic right now, but i wonder how futuristic those early graphical user interfaces like windows seemed way back in the ‘80s. whichever way you look at it,

microsoft seems to be thinking differently to its previous incarnation. it is really interesting, the difference that a ceo makes to even a massive company like this. ok, the previous ceo, steve bulmer, once called open source a cancer, and yet here we are with a company that is embracing all things open source, actively embracing other people's ideas, other people's software, and the numbers don't lie. microsoft is back in the game. it's february and that means it's awards season, and if there's one award that we really love here at click

it's the one for special effects. last year, we talked to the visual effects teams behind all the most amazing looking movies, and over the next four weeks, we are going to be speaking to some of the biggest names in the industry as they tell us how they made some of the biggest films of past year. and frankly, no movie was bigger than avengers: infinity war, so big, in fact, that it needed several effects houses to work on individual sequences in the film, in order to bring's earth's mightiest heroes to life. in time, you will know what it's like to lose, to feel so desperately that you're right, yet to fail all the same. i think it's 3,500 vfx shots, which is a huge number for a film. hear me, and rejoice. it was a major sequence, so it's the part of the film where ebony moore comes down to try and get the time stamp from dr strange. we have a capture lab

here who collect data for us and do motion capture and all that sort of thing, and they went out to greenwich village and i think they pretty much photographed all of it. in terms of the actual set itself, they were acting either on the stage at pinewood atlanta, so that was mainly blue screens. brief was that it was war—torn, the trees were on fire. so all the trees on atlanta had their leaves on them. everything you see, that's close—up and burning. so it's fairly immersive. because we were on the show fairly early, in a preproduction phase, all of the designs of the suits were really only in a 2—dimensional form. so concept artists from marvel had worked those up, and part of our brief was to try to realise them in cg

and realise them in terms of motion as well, how they actually would move and work. so our technology was a big part of that, it's nano—tech. robert downey, jr had quite a bit of input into how that worked. it has a couple of cords that you pull, and the suit tightens and allows the nano—tech to come out and spread over it, which was his idea. spider—man has got his own problems as a character because he's so bendy, and i think quite often, the dislocations in his anatomy that would occur if you got into that kind of position are quite often hidden artfully in lighting. a lot of the effects are defined by the story and the storyboard. so was hone down on what happened to bricks, and making little darts out of bricks that will fly.

he's an alien so it's hard to find a reference. the character is old and quite distinguished, and he's a wizard, so we looked at distinguished looking english actors, like peter cushing and christopher lee. took cues off their hair, and what does their skin look like? and then try and infuse some of that character and posturing into the character. bring me the stone. don't forget, we are all over social media. you'll find us on facebook, on youtube, instagram and twitter, where we live at @bbcclick. thank you very much for watching and we will see you soon. hello.

snow has been the most prominent feature of the weather over much of the last week. but at least on saturday, the sunshine came back. but that's going to be harder to find through much of sunday. as cloud increases, some of us will see a bit more wet weather. but that comes after quite a hard frost to start the day. in fact, some places could well be into minus double figures, where the snow is deepest. you can see the extent of the frost as well, even in town and city centres, it's a cold start to the day. but for many of us, there will be some sunshine, but from the word go, northern ireland and western scotland, more cloud around here and some rain, sleet and snow, courtesy of these weather fronts coming in from the atlantic. and slowly pushing their way a bit further east as we go through the day. now, the early wet weather should be fairly soon out of the way in northern ireland. a damp start here. but again, the rain preceded by a bit of sleet and snow in places, and then that process moves across scotland. into northern england, mayjust fringe north wales. but south of that, it should stay mainly dry. cloud increasing, but still some sunny spells towards east anglia and south—east england.

behind the wet weather, it brightens up again in scotland. but it stays cloudy in northern ireland. further outbreaks of rain coming back going into the evening. and temperatures, they‘ re a little bit higher. parts of south—west england could be up to around 10 celsius, for example. and a freshening south—westerly wind. it gets stronger on through sunday night and into monday morning, as it feeds in more wet weather, and while most of us will see rain out of this, a bit of snow falling into the pennines and southern uplands, but especially into the higher ground north of the central belt in scotland, where we could see around 5—10 centimetres building up as we go on through monday as well. it will be quite slow to clear, on what will be a much less cold start to the day on monday. some rainjust affecting parts of south—east england as monday starts. it may not clear the far south—east. it looks like we'll hold onto an area of cloud here in east anglia. the snowy weather slowly pulling away from northern scotland, and many other areas will see things brightening up on monday. and temperatures again are a little bit higher,

and some of us in south—west england getting into double figures. they'll drop again on monday night and this ridge of high pressure with clear skies, there'll be another frost going into tuesday morning. low pressure gathering to the west, though, sets the scene for quite an unsettled week to come. now, there will be some sunnier days, but there will also be some wetter days. it'll often be windy, but if you take one thing from this chart, it's those temperatures heading upwards. and more of us at times will see temperatures into double figures, and of course, that's going to feel very different compared with what we've had over much of the past week or two. so a change for the milder in the week ahead. you're watching bbc news. i'm reged ahmad. our top stories: tens of thousands take to the streets of venezuela in rival mass rallies for and against president nicolas maduro. there is a sense here of celebration. the mood is relaxed but the intent is serious, to send a message to president nicolas maduro that time is up. russia says it will follow the us,

pulling out of a key nuclear treaty, and also developing a new range of missiles. virginia governor ralph northam refuses to quit and insists he is not the person in a racist photo. in the hours since i made my statement yesterday, i reflected with my family and classmates from the time and affirmed my conclusion that i am not the person in that photo. and punxsutawney phil did not see his shadow.