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)

Dharma the Sumatran tiger yawns as members of the public return to Edinburgh Zoo as it opens for the first time following the easing of Scottish Governments lockdown restrictions on June 29, 2020 in Edinburgh, Scotland. Outdoor visitor attractions in Scotland have reopened along with many non-essential retailers after more than three months in lockdown, as Scotland moves into phase 2 of its “route map” for easing coronavirus restrictions. (Photo by Jeff J. Mitchell/Getty Images)

A woman sits in a cell at the Los Angeles County Women's jail in Lynwood, California April 26, 2013. (Photo by Lucy Nicholson/Reuters)

A farmer arranges vegetable at a greenhouse on January 29, 2021 in Hukou County, Jiangxi Province of China. (Photo by Zhang Yu/VCG via Getty Images)

A Pakistan fan poses for a photo during the Group Stage match of the ICC Cricket World Cup 2019 between Australia and Pakistan at The County Ground on June 12, 2019 in Taunton, England. (Photo by Alex Davidson/Getty Images)

A boy stands near the rotting carcass of a camel that that died of hunger which people had burned to stop the bad smell, in Belif, Garissa county, Kenya on Sunday, October 24, 2021. (Photo by Brian Inganga/AP Photo)

A plane battling the Ferguson Fire passes the setting sun in unincorporated Mariposa County Calif., near Yosemite National Park on Sunday, July 15, 2018. (Photo by Noah Berger/AP Photo)

Fish are thrown onto a truck during a winter fishing festival held on the frozen Wulungu Lake in Fuhai county, Xinjiang Uighur Autonomous Region, January 18, 2015. (Photo by Reuters/China Daily)