A colorful sky at sunset over the snowy mountains in Immenstadt, Bavaria, Germany, 20 November 2014. Cloudy weather is forecast in the region on 21 November. (Photo by Karl-Josef Hildenbrand/EPA)

An aerial view shows the the Mountain Bike course at the X-Park at Deodoro Olympic Park ahead of the 2016 Rio Olympics in Rio de Janeiro, Brazil, July 16, 2016. (Photo by Ricardo Moraes/Reuters)

Bavarian herdsmen and a herdswoman in traditional dresses drive their beasts on a road during the return of the cattle from the summer pastures in the mountains near Oberstaufen, Germany, Friday, September 9, 2016. (Photo by Matthias Schrader/AP Photo)

Visitors walk through a tulip display in Chaya Mountain, Suiping County in Zhumadian, Henan Province of China on March 31, 2016. There are more than ten varieties of tulips here. (Photo by VCG/VCG via Getty Images)

Purev and Buyantogtokh enjoy the warmth of the fire in the snow in Altai Mountains, Mongolia, September 2016. Navigate the snowy wilds of Mongolia with this nomadic reindeer herding family. Photographer Joel Santos dived 1000km into the depths of Northern Mongolia to visit the Ganbaa family near Khovsgol Lake. (Photo by Joel Santos/Barcroft Images)

Two one-year old baby mountain gorillas play together in the forest of Bwindi Impenetrable National Park in southwestern Uganda on Saturday, April 3, 2021. (Photo by AP Photo/Stringer)

A traditional high altitude bonfire burns on the occasion of the Swiss National Day on the “Stanserhorn” mountain near Stans, Switzerland, Sunday, August 1, 2021. (Photo by Urs Flueeler/Keystone via AP Photo)

In this photo taken Friday, September 4, 2015, tourists Sarah and John Scott from Worcester, England, take a step back as a male silverback mountain gorilla from the family of mountain gorillas named Amahoro, which means “peace” in the Rwandan language, unexpectedly steps out from the bush to cross their path in the dense forest on the slopes of Mount Bisoke volcano in Volcanoes National Park, northern Rwanda. Deep in Rwanda's steep-sloped forest, increasing numbers of tourists are heading to see the mountain gorillas, a subspecies whose total population is an estimated 900 and who also live in neighboring Uganda and Congo, fueling an industry seen as key to the welfare of the critically endangered species as well as Rwanda's economy. (Photo by Ben Curtis/AP Photo)