Stefan Dobrovolny of Austria and Inigo Munoz Elorza of Spain (R) stand in front of a quad bike during a simulated Mars mission on Tyrolean glaciers in Kaunertal, Austria, August 7, 2015. The Austrian Space Forum is sending some of its researchers to practice weight-less walking in spacesuits on a glacier which resembles the terrain on Mars. (Photo by Dominic Ebenbichler/Reuters)

Janus, a two-headed Greek turtle named after the Roman god with two heads is testing a kind of skateboard to rehabilitate one day ahead of her 25th birthday at the Natural History Museum in Geneva on September 2, 2022. (Photo by Pierre Albouy/Reuters)

Family members and relatives of passengers on board the Twin Otter aircraft operated by Tara Air, weep outside the airport in Pokhara on May 29, 2022. A passenger plane with 22 people on board went missing in Nepal on May 29, the operating airline and officials said, as poor weather hampered a search operation. (Photo by Prakash Mathema/AFP Photo)

An Ezo red fox, or kitakitsune, and her cub are seen at night near the city of Sapporo, northern Japan, 15 May 2022. Authorities are calling population to avoid contact with the animals due to risks of echinococcosis infection. (Photo by JIJI Press/EPA/EFE)

A woman dressed in an alien space suit carries an American flag and a sign that reads “Women's Revolution 1971” as she marches in a Women's Liberation demonstration on Fifth Avenue in New York, August 26, 1971. (Photo by Marty Lederhandler/AP Photo)

A pro-Russian rebel shows his t-shirt depicting Russian President Vladimir Putin at a checkpoint in the village of Chornukhyne near the town of Debaltseve, north-east from Donetsk, March 12, 2015. (Photo by Marko Djurica/Reuters)

Rescuers pull dead whales ashore in Probolinggo, East Java, Indonesia, Thursday, June 16, 2016 during a mass rescue operation of stranded whales. Most of more than 30 stranded whales were managed to be pulled into the deep sea, an official said. (AP Photo/Trisnadi)

The Vietnam Slide Project was created by photo editor Kendra Rennick, who began collecting photo slides after a close friend lost her father, a Vietnam veteran. Her friend found a box of slides that her father had taken while in Vietnam and from there Rennick has continued to collect photographs that Vietnam veterans took during their tours of duty. Here: A photo taken from the collection of D.Thornton, who served in the First Air Cavalry division of the United States Army. (Photo by D.Thornton/The Vietnam Slide Project)