Vietnam’s Son Doong cave, the largest in the world, could hold a 40-story skyscraper inside. The pristine ecosystem has its own river and jungle. Despite its size, Son Doong wasn’t discovered until 1991. It was lost again for nearly two decades and was fully explored for the first time in 2009. (Photo by Jason Speth/HuffPost)

A woman lies to pose for her souvenir picture on the glass sightseeing platform on Shilin Gorge in Beijing, China, May 27, 2016. (Photo by Kim Kyung-Hoon/Reuters)

A motorist holds on to a post as she braves high winds and rain of Super Typhoon Meranti in Kaohsiung, southern Taiwan, 14 September 2016. The storm is the strongest recorded since Super Typhoon Haiyan developed in 2013. (Photo by Ritchie B. Tongo/EPA)

The bride in her room, prepared for a traditional Chechen wedding ceremony in Grozny, Chechnya, Russia on November 24, 2016. (Photo by Valery Sharifulin/TASS)

A street vendor wearing a Santa Claus costume sits next to a girl at the boulevard of Sabana Grande in Caracas, Venezuela December 19, 2016. (Photo by Marco Bello/Reuters)

Tourists standing near the sea shore are hit by a wave, which surged past a barrier under the influence of Typhoon Chan-hom, in Qingdao, Shandong province, China, July 12, 2015. One of the most powerful typhoons to strike eastern China in decades disrupted air, rail and sea transport on Saturday after forcing the evacuation of more than a million people from the provinces of Zhejiang and Jiangsu, state media reported. (Photo by Reuters/Stringer)

“Serengeti National Park encompasses 5,700 square miles of grassy plains and woodlands near the northern border of Tanzania, and is home to more than 3,500 lions grouped into a couple dozen prides. Photographer Nick Nichols and videographer Nathan Williamson made several extended trips to the Serengeti between July 2011 and January 2013, determined to break new visual ground in their coverage of the Serengeti Lions”. Photo: Cubs of the Simba East pride: too young to kill but old enough to crave meat. Adult females, and sometimes males, do the hunting. Zebras and wildebeests rank high as chosen prey in the rainy season. (Photo by Michael Nichols/National Geographic via The Atlantic)

Icelandic horses walk in their paddock at a stud farm in Wehrheim near Frankfurt, Germany, as the sun rises Tuesday, June 1, 2021. (Photo by Michael Probst/AP Photo)