Policewomen take a picture inside a tunnel under the Chao Phraya river at a Mass Rapid Transit subway station in Bangkok, Thailand, December 14, 2015. (Photo by Athit Perawongmetha/Reuters)

Visitors wear shirts with an image of former Chinese leader Mao Zedong at the Shanghai World Expo site in Shanghai, May 2, 2010. (Photo by Aly Song/Reuters)

In this January 27, 2015 photo, penguins walk on the shore of Bahia Almirantazgo in Antarctica. Antarctica “is big and it's changing and it affects the rest of the planet and we can't afford to ignore what's going on down there”, said David Vaughan, science director of the British Antarctic Survey. (Photo by Natacha Pisarenko/AP Photo)

Two F-15E Strike Eagles wait to receive fuel from a KC-135R Stratotanker during exercise Red Flag 15-1 on their way to Nellis Air Force Base, Nev., Jauary 23, 2015. The F-15s are assigned to the 4th Fighter Wing. U.S. (Photo by Airman 1st Class Aaron J. Jenne/Reuters)

A new book of photos by legendary photographer Weegee shows what industrialized, pre-gentrified New York looked like in the mid-20th century, before the city was crammed with towers and billboards. Here: this combination shows the 1945 photo “Derelict sleeping on the sidewalk outside police headquarters” by Weegee, provided by the International Center of Photography in New York, and a woman walking on the same spot on Wednesday, March 18, 2015. (Photo by AP Photo/Copyright Weegee/The International Center of Photography, Mark Lennihan)

A hungry cow smiles for the camera in Salzburg, Austria. One of a series of funny animal mugshots taken by Chanel Cartell and Stevo Dirnberger during their travels around the globe. (Photo by Chanel Cartell/Stevo Dirnberger/Rex Features/Shutterstock)

According to the U.S. government, Moldova, one of the poorest countries in Europe, depends on about $1.6 billion annually sent back from the roughly one million Moldovans who left for work in in Europe, Russia, and other former Soviet Bloc countries. Photographer Myriam Meloni went to Moldova to document what she refers to as “social orphans” – children whose parents have emigrated to another country in search of a job and a better future for their families. Here: Lulia is seen washing dishes in her grandmother's house, where she lives. (Photo by Myriam Meloni)

Pfc. Sebastian Rodriguez, machine gunner, Weapons Platoon, Lima Company, 3rd Battalion, 3rd Marine Regiment, Marine Rotational Force – Darwin, fires an M240 machine gun during a night squad-attack exercise, here, May 22, 2013. (Photo by Sgt. Sarah Fiocco/U.S. Marines)