week, numbers cooling off, heading towards wednesday. >> all right, nbc nightly news is next, and more local at 6:00. >> we'll see you then. on this sunday night, no end in sight. more rocket attacks on israel as israel steps up its campaign that sent thousands including many americans fleeing. lightning strikes. another deadly summer as two more people are killed over the last two days. tonight why so often victims never know they are in danger. warning signs. the simple test that could reveal early on whether you might develop alzheimer's disease. and world cup fever. amid the hoopla over the last month, has soccer really made it into the big leagues here in the u.s. >> announcer: from nbc news world headquarters in new

york, this is "nbc nightly news" with lester holt. good evening. the death toll inside gaza has climbed considerably since we were with you last night, as hamas and israel showed no signs of ending the bloodshed. israel today issuing a warning that sent thousands inside gaza, including many americans, fleeing for their lives. this, as hamas fighters launched more rocket attacks against israel. most were either intercepted or fell harmlessly short of their targets. really counterattacks are taking a heavy toll inside gaza, where the death toll has now climbed to at least 172. more than 1,100 people have been wounded. tonight for the first time israel is pointedly telling some palestinians to leave their homes, warning, israel will, quote, strike with might. we have full coverage from the middle east to washington. we begin with nbc's ayman inside gaza tonight with the latest. ayman? >> reporter: good evening, lester. six days into this conflict, all

indications suggest the fighting is intensifying. they said they destroyed long-range palestinian rockets deep inside the territory. it also began calling and dropping leaflets on thousands of palestinians, saying leave your homes or risk facing danger. more importantly, the u.s. embassy evacuated about 150 americans that were trapped in gaza. from the skies above, and the sea, israel is stepping up its campaign to destroy rocket sites in gaza. warning residents by phone and leaflets, leave your homes or risk being injured. in the middle of the night thousands of palestinian families began leaving with what little they have. some of the children barely had time to put on their shoes before escaping. thousands, the u.n. said, have already taken refuge at schools now used as makeshift shelters.

while some families fled the fighting, others moushd those killed in it. overcome by grief, this woman who lost three of her children fainted. mourners prayed for the dead. 13 of them were from one family. relatives of gaza's police chief who israel targeted in the deadliest air strike since the fighting began. 18 others were killed. including ahmed's parents and four siblings. a palestinian child now orphaned by yet another war. for some, the violence has become unbearable. today the u.s. evacuated its citizens with the help of the u.n., making the journey with this man and his family from houston, texas. they were here visiting relatives. now too afraid to stay. do you feel bad about leaving gaza right now? >> very.

i'm leaving, yet my buddy is leaving, my heart is staying back home. my heart is staying in gaza. >> reporter: an escape to safety for one american family that very few palestinians in gaza will have. lester, the u.n. said it is trying to prepare as many schools as possible. some of those schools have already been damaged in the fighting. and meanwhile, palestinian health officials are expressing grave concern about the health infrastructure here. they say they simply can't cope with the casualties in the event there is a ground invasion. lester? >> ayman, thank you. let's get the latest from inside israel. middle east correspondent martin fletcher joins us now from tel aviv. martin? >> reporter: hi, lester. good evening. well, israel's saved again today by the iron dome. hamas firing more than 100 rockets at israel today. they were shot down by the anti-rocket system. one teenager was hit by falling metal debris.

now, hamas fired more than 900 rockets in the last week, and he's the first israeli to be hurt from a rocket. they're waiting for the order to invade. a senior army told the press today israel will, quote, strike with might from this evening. it isn't clear that means more attacks from the air, or whether troops will go in on the ground. but clearly, northern gaza is the target. as ayman mentioned earlier, smaller units already did go into gaza, israeli soldiers. as far as we know, they're the first to go in. a commander unit from the navy destroyed a rocket launcher facility that the army said could not be hit from the air. four of those israeli soldiers were lightly wounded, but they're all home now and the army said they accomplished their mission. prime minister netanyahu said today that israel would not bow to pressure to call a cease-fire. not until israel's achieved its goal of stopping all rocket fire from gaza. he said the attack could go on for a long time.

but you know, lester, the more palestinian dead there are, the more forced from their homes, the more international pressure is building on israel to stop their assault. lester? >> martin fletcher in tel aviv tonight, thank you. now to u.s. efforts to broke a cease-fire. senior white house correspondent chris jan sing is with us now with the latest from there. chris? >> reporter: there's been a barrage of phone calls with the israeli prime minister benjamin netanyahu with the president on thursday, more from secretary of state john kerry, including one today. a state department official said kerry again stressed as the president did that the u.s. wants to play a role in de-escalating the violence. while repeatedly reaffirming israel has the right to defend itself, they're calling for a cease-fire from france and britain. so what more specifically can the u.s. do?

diplomacy in the middle east is always complicated. officials here do not talk directly to the leaders. the administration has vowed to use its relationship in the region to try to broker that cease-fire. but, of course, going to have to put a lot of pressure on both hamas and israel, lester. >> as we recall 2012 egypt stepped forward to help broker a cease-fire. what are the options in terms of other countries that might take that role this time around? >> reporter: they're not great, lester. egypt again, tony blair acting as a special envoy on behalf of the u.s., the european, russia and the u.n. meeting with the egyptian president. former president morrissey was ousted in a coup. turkey, that relationship is also fractured. one other possibility may be qatar. but in response to questions on friday, and today, the white house did not say the president would dispatch secretary kerry

to the region this week. lester? >> kris jan sing at the white house, thank you. severe weather in the u.s. has produced deadly lightning strikes. two people were killed by lightning in two days, both in colorado's rocky mountain national park. nearly two dozen others were injured. we get details from nbc's ra ha meth ellis. >> reporter: now there's concerns about deadly weather. >> a group of people trying to get down a trail was hit by lightning. >> reporter: in the past two days, 12 people in the mountains have been struck by lightning. >> you get burns on the feet because of the way the electricity spreads on the ground. >> reporter: two people died, including a 42-year-old. she was hiking with her husband on friday. lightning fatalities occur mostly during summer months when outdoor activities and thunderstorms are more common. since 2006, there have been 270

deaths, including 9 this year. nationwide, in an hour's time today, there have been more than 22,000 lightning strikes. >> my god! >> reporter: in tennessee last month, lightning caused a fire at this church. in florida, boaters billy and his son consider themselves lucky survivors after lightning hit their boat's antenna. >> my hand went totally numb, changed colors. the knee hurt pretty good. i looked at it. it had really went to really strange dark purple/blue. >> reporter: scientists say people should be careful. even if the lightning appears far away. >> it can be anywhere within five, ten miles of a storm. lightning can strong from a long distance, even if the storm is not on top of you. >> my god! >> reporter: experts say if you hear thunder, get inside. to be safe from potentially

deadly lightning that can strike in a flash. . more severe weather in the forecast. a midsummer cold snap from the nation's midsection. meteorologist kim cunningham is here with us now for more on that. >> for the northeast as well. remember, if you can hear thunder, you can get hit by lightning. something to remember if you're heading to the beaches. another thing to remember, severe weather threat is going to be with us over the next couple of days. we have storms right nowoving off to the east. we've had reports of wind damage. the cold front off to the west. another one behind it. once the second cold front comes through, that's when we'll see the really cool air coming into the midwest and northeast and bring relief. humidity levels are extremely high in some cases. very strong upper-level trough. the jet stream, the cold front moving east. moisture coming up from the gulf of mexico. all coming together for the

cooldown for the northeast over the next couple of days. expect temperatures in the 70s tonight. but we will see temperatures cooling down tomorrow. temperatures will be in some areas in the 80s. again, cooling down by the weekend. back to you, lester. >> kim cunningham, thank you. important medical news tonight. alzheimer's researchers report simple eye and smell tests may detect early warning signs of the disease. the findings of four studies were presented today at an alzheimer's conference in copenhagen. chief medical editor, dr. nancy snyderman. >> reporter: at 71 years old, jane says she has to work a little harder at remembering things. >> it's like i'm not keeping as much at my fingertips. >> reporter: she doesn't have alzheimer's disease, but for jane and millions of other americans, it's hard to recognize when the symptoms of normal brain aging are developing into something more serious. >> i hope that doesn't happen for my family's sake, for my children's sake.

>> reporter: jane is participating in a new study that could help doctors detect alzheimer's disease earlier. for the last four years, more than 200 participants in the harvard aging brain study were given smell identification tests, along with memory evaluations, and brain scans. >> individuals that have worse smell identification performance also had evidence of degeneration in two areas of the brain. >> reporter: new research like this finds changes in sensory symptoms like smell and vision may be early indicators of the disease. doctors have found that eye examinations can show buildup in the brain of beta amaloiyd, associated with alzheimer's disease. as many as 16 million people over the age of 65 could be diagnosed by 2050. three times the diagnosed cases today. doctors hope advances in early detection like eye and smell testing may one day reverse this

trend. >> it may not be the sole indicator of alzheimer's, but it could be an indicator that tells the eye doctor, for example, that a person should go on and get a more distinct workup. >> reporter: early indicators that begin with innovative research. >> i hope that it helps in understanding alzheimer's, and from there, would come some way of treating it. >> reporter: as doctors get closer to finding answers to a disease that still remains a medical mystery. dr. nancy snyderman, nbc news, new york. desperate efforts to save children from becoming victims of a deadly superstition. and later, amid a friendsy over the world cup. has the world cup finally taken hold in the u.s.

the pki school girl who survived being shot in the head by the taliban is pledging to help free the school girls kidnapped by islamic extremists in nigeria. nearly three months ago. she held an emotional meeting in nigeria's capital today for the parents of nearly 300 girls held by boko ha ran. now, another inspiring story. two unlikely friends challenging ancient beliefs in an african nation. it all happening in the remote omo valley in southern ethiopia. here's indianapolis's ann curry. >> reporter: the little ones at the omo children's home have a simple name for this man -- dad.

but as they grow older, they will learn he is so much more. because he saved their lives. >> what was your impression of him? >> what incredible wisdom he had. >> reporter: the story might never have been told but by john rowe who ventured into the omo valley as a photographer, and hired lolly as his guide. >> lolly was this wise old sold whom i connected to. and came to trust and love like a son. >> reporter: after numerous trips, lolly revealed an almost unimaginable superstition held by his people. babies whose top teeth appear before their bottom teeth or born out of wedlock were believed to be cursed. bringing drought or disease to the tribe, so they were killed. >> i said, one day i'm going to fix this problem. >> reporter: lolly asked for john's help.

>> we're going to draw a line in the sand right here. these kids are going to be okay. we're going to protect them. >> reporter: supported by john, lolly risked his life as he along with volunteers slipped into villages and rescued children one by one like baby jessica. they were driven by images like this. another little girl on the verge of death. a haunting reminder to lolly of two sisters he lost to the deadly superstition. you miss them even though you never missed them. >> yes, i miss them a lot. >> reporter: undeterred by death threats, lolly has saved some 40 children. his greatest achievement came on the day he convinced tribal elders to end the ancient practice once and for all. today lolly is raising the children he saved, nurturing them, educating them.

remember baby jessica? here she is today. and that skeletal baby girl? she is now a happy toddler. >> you look at the children that lolly saved and you see their smiles and singing and running around and they're happy. it brings you joy. >> reporter: innocence once lost is now found. ann curry, nbc news. coming up next, the extraordinary operation set to begin tomorrow to raise the shipwreck costa concordia.

the outfit worn by tv's lone ranger brought in a texas size haul at auction, cowboy boots and a holster made with two custom-made colt pistols. actor clayton moore wore it during appearances he made after retiring from tv. it sold for $195,000 to an undisclosed buyer. an unprecedented operation to raise the costa concordia is set to begin tomorrow off italy where the cruise ship ran aground and sank two and a half years ago killing 32 people. it involves pumping air into 30 flotation devices that have been welded to the sides of the ship. which is twice the size of the "titanic." once raised, it will be towed

away and broken up for scrap. a selfie could prove costly. he didn't get hurt during his adventure on thursday, but he reportedly faces the equivalent of $4,100 fine for putting people in danger, as he snapped a picture while running ahead of the charging bulls. meantime, an italian racer in the tour de france was caught texting yesterday. a sports photographer tweeted out this picture. the rider was given a warning by officials that using your cell phone during the race is forbidden. we hope they didn't tex that warning to him. mean time in san francisco, an awesome group of nfl legends returned to the feel for the final football game ever at candlestick park. an all-star team led by the 49ers four-time super bowl winning quarterback joe montana faced off in a charity flag football game against a team, captained by famed miami dolphins quarterback dan marino. among the other greats taking part, jerry rice, white clark and steve young.

built in the late 1950s, the former home of both the 49ers and san francisco giants is scheduled to be demolished next spring. still ahead, amid the world cup frenzy, has soccer finally arrived in the big leagues of american sports.

germany reigns as world cup champions for the fourth time. angela merkel was on hand as germany lifted the trophy.

the winning goal was actually scored by a substitute at the 113-minute mark. so, after a month now of world cup hoopla, has soccer been elevated to a super sport status here in america. here's nbc's jenna wolf. >> i believe that we will win! >> reporter: this summer the world's most popular sport became america's most popular sport. >> usa! usa! >> reporter: our emotional attachment to the game may not be intense as, say, that of the br zil yans. was the most popular sport? >> soccer. >> reporter: what's number two? >> i don't know. >> the fact we had 200,000 americans traveling to brazil to watch this world cup is a testament to how big soccer's becoming in this country. >> reporter: the u.s.-portugal match was the most watched ever, more than the 2013 world series. close to 25 million. now that the world cup is over,

will americans still be talking about soccer tomorrow. >> we're getting there. for that reason, i think that it's growing exponentially. >> it's hard to say, because football season is around the corner. >> reporter: dozens of kids came out this morning for soccer camp. >> what sport are you playing? >> soccer. >> you're playing soccer? what are you playing? >> soccer, too. >> you guys all play soccer, right? how many of you guys watched the world cup? raise your hand. >> when you have a kid here that says they're watch the world cup, all the other kids start to listen. >> reporter: when i dug a little deeper, can you name a famous soccer player? >> the only soccer player i know is -- >> reporter: how many of you guys can name any player on any soccer team? >> england. >> reporter: name any soccer player in the whole world. >> torres? >> reporter: that's one. how about another one? at least we're headed in the

right direction. >> it's growing exponentially. is it going to be the nfl in the next few years? no. but one day it will sit at the head table with these other major sports in america. and be recognized as what it is, the number one sport in the world. >> reporter: germany and argentina may have the last word on the field, but it's the little moments off the field that will determine the future of soccer in america. jenna wolf, nbc news, new york. that's "nbc nightly news" for this sunday. brian williams will be here tomorrow. i'm lester holt reporting from new york. for all of us here at nbc news, new york. for all of us here at nbc news, good night. -- captions by vitac -- www.vitac.com

fire comes close to bay area homes. crews battle flames and hot, dry conditions. the latest as crews remain on scene watching for hot spots. high-end shops in union square closed for business. the damage caused by flooding and hear from the people who are disappointed. air strikes and fighting intensify in the middle east. tens of thousands told to evacuate as israeli troops move into gaza. i'm terry mcsweeney. >> i'm peggy bunker. new details on a grass fire in fairfield. the fire is now contained but earlier several homes were evacuated. those people have been let back in. the fire broke out about 2:00 in a g