Camera trapper Xavier Hubert-Brierre put this large mirror on the side of a road through the jungle in Gabon and left a camera there to record how the animals would respond to their own reflections. A silverback gorilla thought it was seeing another silverback and responded by trying to scare off the potential challenger… (Photo by Xavier Hubert-Brierre/Johns Hopkins University Press)

Vendors sell clothes on the roadside at a second-hand street side clothing market in Mumbai January 28, 2015. The market is open daily for three hours and hundreds of vendors gather to barter or sell used clothing. (Photo by Danish Siddiqui/Reuters)

A female Indian rhinoceros called Maruska eats a vegetable birthday cake on her first birthday celebration at the Plzen Zoo on February 3, 2015 in Plzen, Czech Republic. (Photo by Ladislav Nemec/Isifa)

Damaged vehicles sit on Yeongjong Bridge in Incheon, South Korea, Wednesday, February 11, 2015. Two people were killed and at least 42 were injured on Wednesday after a pileup involving about 100 vehicles in foggy weather on the bridge near the Incheon International Airport, South Korean officials said. (Photo by Suh Myung-gon/AP Photo/Yonhap)

U.S. singer Katy Perry slips on the icing of a giant cake that she had jumped onto as part of her performance at the MTV Latin America Awards in Guadalajara, in this October 16, 2008 file photo. (Photo by Daniel Aguilar/Reuters)

Runners rest inside Kim Il Sung Stadium in Pyongyang, North Korea on Sunday, April 14, 2013. North Korea hosted the 26th Mangyongdae Prize Marathon to mark the upcoming April 15, 2013 birthday of the late leader Kim Il Sung. (Photo by Alexander F. Yuan/AP Photo)

A woman poses as she has her picture taken amid 1600 panda bear sculptures in Berlin August 5, 2013. Marking the 50th anniversary of its existence, on Monday the German branch of the World Wide Fund for Nature (WWF) environmental conservation organisation placed 1600 panda bear sculptures on front of Berlin's main train station to draw attention to the plight of the endangered species that serves as the NGO's mascot. There are currently 1600 panda bears alive in the wild, the organisation said in a press release. (Photo by Thomas Peter/Reuters)

A window cleaner passes a lighter to his colleague while rappelling from a new building in Tianjin March 23, 2007. (Photo by Reuters/Stringer)