A woman looks out of the bus window at a man climbing on the outside, in Sevare, Mali. Eric Gaillard/Reuters
A fighter from the Free Syrian Army's Tahrir al Sham shouts during heavy fighting in the Mleha suburb of Damascus, Syria. Goran Tomasevic/Reuters
Arctic wolves stand in an enclosure at Wolfspark Werner Freund, in Merzig, Germany. The wolves, acquired as cubs from zoos or animal parks, were mostly hand-reared. Spread over 25 acres, Wolfspark is currently home to 29 wolves forming six packs from European, Siberian, Canadian, Arctic and Mongolian regions. Lisi Niesner/Reuters
A protester opposing Egyptian President Mohamed Morsi gestures at riot police during clashes along Mohamed Mahmoud street which leads to the Interior Ministry, near Tahrir Square in Cairo. Amr Abdallah Dalsh/Reuters
Bill Demong of the USA soars through the air during the individual Gundersen competition at the Nordic Combined FIS World Cup in Klingenthal, Germany. Jens Meyer/AP
Horses running through a forest path covered with snow near Bosnian town of Banovici, about 60 miles north of Sarajevo, Bosnia. Amel Emric/AP
A reveller dressed as a character from the science fiction film Avatar holds his ripped drum at the 'Desliga da Justica' carnival block parade, a pre-Carnival celebration, in Rio de Janeiro, Brazil. Felipe Dana/AP
Camels rest before a weekly camel race ridden by robot jockeys at the Kuwait Camel Racing club in Kebd. The robots are controlled by trainers, who follow in their vehicles around the track. Stephanie McGehee/Reuters
Swimmers in fancy dresses take a bath in the Danube river near Neugurg, southern Germany, during the annual Danube fun swimming event. Karl-Josef Hildenbrand/dpa/AP
Foreign devotees carry a female friend at the Sangam, the confluence of the rivers Ganges, Yamuna and mythical Saraswati, during the Maha Kumbh Mela in Allahabad, India. During the festival pilgrims bathe in the holy Ganges River in a ritual they believe can wash away their sins. Rajesh Kumar Singh/AP
An award-winning director discusses the challenges of making a documentary about a top secret digital weapon. Officials from both countries believed to be responsible for the virus meant to slow Iran's nuclear program won't publicly acknowledge it ever existed.
In his recently released film "Zero Days," award-winning documentary filmmaker Alex Gibney takes on an especially tough challenge: Making a movie about a top secret program that few people will publicly acknowledge ever existed.