A Bosnian special forces soldier returns fire 06 April 1992 downtown Sarajevo as he and civilians come under fire from Serbian snipers. The Serb extremists were shooting from the roof of a hotel at a peace demonstration of some of 30,000 people as fighting between Bosnian and Serb fighters escalated in the capital of Bosnia- Hercegovina. (Photo by Mike Persson/AFP Photo)

Mangrove in Walakiri Beach after Sunset in East Sumba, Indonesia in 2018. (Photo by Sarubabel Malau/Rex Features/Shutterstock)

Juno, a Beluga whale, greets a young viewer at the Mystic aquarium in Connecticut, USA on December 5, 2015. (Photo by Tim Clayton/Corbis)

On the western side of Mount Hood lies the longest glacier cave system in the contiguous United States. In 2012, these caves were mapped to a combined length of 7,166.8 feet by cave explorers Brent McGregor and Eddy Cartaya. Currently, the total passage length is hundreds of feet less. Glaciers are frozen rivers; they are always moving and changing... (Photo and caption by Josh Hydeman)

A villager run as Mount Sinabung erupt at Sigarang-Garang village in Karo district, Indonesia's North Sumatra province, February 1, 2014. Four people died and more than 28, 000 villagers have been evacuated since authorities raised the alert status for the volcano to the highest level in November 2013, local media reported on Saturday. (Photo by Reuters/Stringer)

These stunning images show the beauty and drama of Mother Nature at work. Captured deep in heart of the Danakil Desert in East Africa, the images show the acid pools near the Erta Ale volcano. Pools of brightly colored acid can be seen amid the dramatic blast of volcanic ash. The photos were taken by Neta Dekel, an Israeli photographer. He the acid pools were one of the most extraordinary sights he had ever seen. (Photo by Neta Dekel/Caters News Agency)

In the works of a photographer named Dave – who goes by Freaktography and never gives out his full name – haunting abandonment leaps from images of discarded machinery, tools and factory essentials. (Photo by Freaktography/Caters News Agency)

A robot is seen on Mount Etna, Italy on July 4, 2017. Mount Etna, in Sicily, is a test bed for the approximately three-foot high, four-wheeled machine ahead of a future mission to the moon. It is being conducted by the German Aerospace Centre, the agency which runs Germany's space programme. (Photo by Antonio Parrinello/Reuters)