The photos were taken at the Piton de la Fournaise volcano on Reunion Island, a French island in the Indian Ocean one of the most active volcanoes in the world. Here: The powerful erupting volcano. (Photo by Luc Perrot/Caters News)

Tianmen Mountain is a mountain located within Tianmen Mountain National Park, Zhangjiajie, in northwestern Hunan Province, China.

Displaced Sunni people, who fled the violence in the city of Ramadi, arrive at the outskirts of Baghdad, April 17, 2015. Iraqi security forces fought Islamic State militants at the gates of the western city of Ramadi on Friday, and local authorities warned it was in danger of falling unless reinforcements arrived soon. (Photo by Reuters/Stringer)

A man standing on the first cables during the construction of the Golden Gate Bridge with the Presidio and San Francisco in the background, San Francisco, California, 1935. (Photo by Underwood Archives/Getty Images)