richard engle continuing his reporting in cairo tonight. richard, thanks. >>> we talked about social media. one more word on that specifically twitter. this crisis spread like wildfire on twitter and other services. we have a live feed up here now, you can look over my shoulder. these are all actually slower than realtime comments. anyone who is leaving a twitter comment, talking to each other on the subject of the uprising in egypt, it's going that fast. there's that many of them. if anything, it slowed down to accommodate all the traffic. and this is despite the fact that egyptians shut down the internet there in egypt. a british newspaper put together a graphic of internet traffic. you see it falls off a cliff when, assuming along with the cooperation of service providers, they shut off internet service. but resourceful people in this electronic age have found a way to communicate with the outside >>> we'll take a break at this point. when we come back, some of the day's other news. the shootout inside a police precinct tonight. the video

and this country does control the suez canal, so a lot is riding on this. >> richard engle in cairo. he'll be covering the story when day breaks there. richard, thanks. >>> now we go to south africa where the news turned ominous earlier today about one of the towering figures of our time, nelson mandela. rumors and anxiety spread concerning his condition and his health after the former president spent the night in a johannesburg hospital. we get an update tonight from johannesburg. good evening. >> reporter: good evening, brian. a day of confusion and concern about the health of nelson mandela. very little official information coming out and millions of south africans are really hungry to hear more information about the health of their great icon, now 92 years old and very frail. he was taken into the hospital yesterday after having difficulty breathing. tonight a spokesman for the mandela family said that he was in good spirits. they said that they were hopeful that he was being treated well for his lung condition and that he might be released perhaps as soon as tomorrow. now, amongs

richard engle has been given rare access to one of iran's secret nuclear facilities just days before iran is scheduled to meet with world powers in istanbul over its nuclear program. a program it says is for making nuclear fuel and not weapons. and so tonight here is what richard found when he was escorted through the facility. >> reporter: at the tehran research reactor, we're first asked to wear lab coats. >> this is probably the most important piece of the equipment. >> reporter: and pocket-sized radiation detectors. precautions because the reactor is on. we pass through two thick metal doors to enter the reactor, built by the united states before iran's 1979 islamic revolution. now a portrait of ayatollah khomeini hangs on the wall. the core is about 25 feet below the surface of a cooling pool. the water glows with an incandescent blue light. it is very unusual for iran to allow anyone to tour its nuclear facilities, let alone take television cameras inside. the people here seem uncomfortable that we're here. we haven't been able to talk to any scientists directly and we're not a