i'm thuy vu. >> and i'm scott shafer.tonight's show, a look back at the bay area's past, present and a glimpse of its future. we begin with an event that happened 100 years ago, the 1915 world's fair. as joshua johnson shows us, it helped transform san francisco into the kozcosmopolitan center that it is today. >> they called it the jewel city. it rose from the mud flats of san francisco's waterfront. a cosmopolitan wonderland built to last just ten months. one of the only vestiges of this lost city is this building, the palace of fine arts. but in 1915 this was just one of many grand palaces that lined the avenues of a 635-acre mini metropolis constructed to host the world's fair in the area known today as the marina district. the fair drew some 19 million people, mostly for the thrill of exploring displays and demonstrations that highlighted the progress of industry, technology, and culture over the centuries. >> if you pushed through the turnstiles, you'd find yourself directly in front of a 435-foot-tall stepped tower

i'm thuy vu. last june, we learned the national security agency has been collecting americans' phone records and e-mail for years. as a national conversation continues about the federal government's access to private information, local law enforcement in california are experimenting with new crime-fighting tools -- eyes on the street and in the skies feeding images to command centers. amanda pike with the center for investigative reporting shows us some of the new technologies now being tested. pike: officer rob halverson of the chula vista police department is testing a technology that could change how police fight crime. [ police radio chatter ] he's on a call to verify the identity of a woman just arrested for possession of narcotics. [ dog barks ] he doesn't need to ask her name or check her i.d. he just takes her picture. halverson: just look here, please. pike: his tablet uses facial-recognition software to find the suspect's mug shot and criminal history. halverson: you can lie about your n

i'm thuy vu.onight we're going to talk about how law enforcement and hackers can track your cell phone. later in the show you'll hear from a stanford researcher about how much one sensor in your phone can reveal about you. but first, we're going to talk about devices known as stingrays, amberjacks, and triggerfish. these are devices police use to track the location of cell phones. they mimic cell phone towers and trick your phone into sending a signal with its location and other information. police say these devices can help them locate suspects and missing persons. but privacy advocates point out the devices can also collect information on every mobile phone in the area. law enforcement officials don't like to talk about this surveillance technology. documents show that some bay area police departments including oakland, san francisco, and san jose already own these devices. this week the santa clara board of supervisors approved the sheriff's request to buy the technology. but as you're about to

i'm thuy vu.ay the commissioner of the national football league, roger goodell, promised the nfl would do more to protect players. >> and we are establishing the position of a chief medical officer. this individual who we expect to have in place very soon, will oversee our medical-related policies. >> over the past year a series of investigative reports revealed the extent to which the nfl had tried to deny the link between football and brain damage. questions about the sport's safety and its future are looming over this weekend's super bowl. half of all americans now say they don't want their children playing football. scott shafer is here to discuss those questions with a former 49er a high school football coach, and an investigative reporter with espn. >> joining me now to discuss football's concussion crisis are espn sportswriter mark fainaru-wada. he's co-author of "league of denial denial," which exposed the nfl's efforts to deny the long-term impacts of concussions. dwight hicks, a former a

i'm thuy vu.ht we're going to talk about how law enforcement and hackers can track your cell phone. later in the show you'll hear from a stanford researcher about how much one sensor in your phone can reveal about you. but first, we're going to talk about devices known as stingrays, amberjacks, and triggerfish. these are devices police use to track the location of cell phones. they mimic cell phone towers and

i'm thuy vu. >> and i'm scott shafer.tonight's show, a look back at the bay area's past, present and a glimpse of its future. we begin with an event that happened 100 years ago, the 1915 world's fair. as joshua johnson shows us, it helped transform san francisco into the k