and additional support from the park foundation, the ford foundation, the wyncote foundation and the frontline journalism fund. >> corporate funding for frontline is provided by: >> narrator: 70 years ago, in april 1945, camera crews with the british and american armies entered the nazi death camps and filmed the horror they found there. the edited film remained unfinished, with missing soundtracks-- stored for decades in the archives of the imperial war museum in london. the film's directors, including alfred hitchcock, had developed a script to go with the pictures. so in 1985 frontline reconstituted the as closely as possible to what we believe the producers intended they made it as a document to serve our collective memory. at least six million people died in nazi germany's system of camps. more than three million were jews. (militaristic music playing) >> trevor howard: in march 1933, 17,264,296 germans voted for the national socialist party. 20,680,000 others cast their vote for democrats, communists christian socialists, people's party, et cetera, et cetera. lack of unity amon

the wyncote foundation. and by the frontline journalism fund, with major support from jon and jo ann hagler. >> corporate funding for frontline is provided by >> whether it's discovering an aspirin a day can prevent heart attacks worldwide, or creating cells that regenerate new heart muscle, our goal is developing treatments that save lives. brigham and women's hospital. >> al ahmad: i came to yemen to try and understand what is driving the groups now fighting for control of the country. (gunshots) in particular, i wanted to meet the houthi rebels. the houthis had mobilized thousands of fighters, and by last fall they had begun pushing south from their northern stronghold close to the saudi border. yemen's government was weak, its army fractured. the houthis saw an opportunity. when i first arrived several months ago, the houthis had already pushed into the capital, sana'a. the houthis are mostly zaidi muslims, from the shia branch of islam. their slogan is now seen everywhere. it's a political chant from th

the wyncote foundation. and by the frontline journalism fund, with major support from jon and jo ann hagler. and additional support from millicent bell through the millicent and eugene bell foundation. corporate funding for frontline is provided by... >> whether it's discovering an aspirin a day can prevent heart attacks worldwide, or creating cells that regenerate new heart muscle, our goal is developing treatments that save lives. brigham and women's hospital. >> sebastian rotella: it was july 2009. a man from america had come here to copenhagen on business. but first, some sightseeing. >> first of all, he rents a bike, an ordinary bicycle. and he has his video camera, and he rides with one hand on the handle and holding the video camera, riding around and taking pictures. you know, it's such an unusual scene of someone biking along with a camera. >> this is the famous concert hall built in 1748. >> rotella: these are his actual recordings as he narrated the images along the way. >> rotella: he might have b