Jaime “Ka Diego” Padilla (R), spokesperson of the Melito Glor Command of the New People's Army (NPA), and Ka Kathryn (Comrade Kathryn) (L) react during their 50th founding anniversary celebration at an undisclosed location in the mountains of Sierra Madre, Philippines, 31 March 2019. (Photo by Alecs Ongcal/EPA/EFE)

A drone photo shows fall folaige wih tones of yellow, red and brown colors of Uludag Mountain, one of the most significant winter tourism destination of Turkey, on November 29, 2020 in Bursa, Turkey. (Photo by Sergen Sezgin/Anadolu Agency via Getty Images)

Mare Sorie, left, and her friend Tsehaynesh Golja, right, take a rest as they carry bundles of firewood from the forest around Entoto mountain near Addis Ababa, Ethiopia Friday, July 17, 2020. (Photo by Mulugeta Ayene/AP Photo)

A federal agent removes mud from a house damaged by a mudslide in Xaltepec, Mexico, Monday, August 8, 2016. Mountain communities in two Mexican states are recovering from weekend mudslides that killed dozens during heavy rains brought by remnants of Hurricane Earl. (Photo by Pablo Spencer/AP Photo)

Bronze medalist Carlos Coloma Nicolas of Spain celebrates after finishing third in the cross-country cycling mountain bike race at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Saturday, August 20, 2016. (Photo by Patrick Semansky/AP Photo)

A pilot inflates his balloon before the 37th International Hot Air Balloon Week in Chateau-d'Oex, January 24, 2015. According to the organizers, over 80 balloons from 20 countries are participating in the ballooning event in the Swiss mountain resort. (Photo by Pierre Albouy/Reuters)

“Winter Climbing from inside Ben Nevis”. The view from inside the mountain, as a winter climber passes through the cave on Minus Three gully. Photo location: Ben Nevis, Fort William, Scotland. (Photo and caption by Daniel Wildey/National Geographic Photo Contest)

Athletes in action during the international parachuting competition Mountain Gravity in Quinto, Switzerland, 27 August 2015. Some 200 participants from all over the world are expected to jump at the event running from 22 to 30 August 2015. (Photo by Samuel Golay/EPA)