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)

A photographer has captured these eerie images showing the scale of some of Britain's deepest darkest wonders. Mike Deere, from Reading, heads to daunting locations such as abandoned mine shafts, miles of sewer tunnels that snake underneath London and even disused cooling towers. Photo: This incredible picture was taken at the Box Freestone Mine, in Wiltshire. Mike revealed that even experienced map readers would struggle to navigate their way around the seemingly endless tunnels that he and his friends visit. (Photo by Mike Deere/Caters News)

Commuters wearing face masks jostle for a ride on a bus discarding social distancing guidelines in Kolkata, India, Tuesday, July 21, 2020. With a surge in coronavirus cases in the past few weeks, state governments in India have been ordering focused lockdowns in high-risk areas to slow down the spread of infections. (Photo by Bikas Das/AP Photo)

A woman walks past posters bearing the letter “Z” in the colours of the ribbon of Saint George, which has become a symbol of support for Russian military action in Ukraine, and reading “We are proud of Russia! We are not ashamed!” at a bus stop on Nevsky Prospekt in central Saint Petersburg on March 15, 2022. (Photo by AFP Photo/Stringer)

A woman looks out of a dusty window after boarding a bus to be transported to see the casket of Nelson Mandela at the Union Buildings in Pretoria, South Africa, Wednesday December 11, 2013. On Thursday, December 5, 2013, Mandela died at the age of 95. (Photo by Markus Schreiber/AP Photo)

Passengers ride an overcrowded bus as they head towards their village to celebrate "Dashain", the biggest religious festival for Hindus in Nepal, as fuel crisis continues in Kathmandu, October 20, 2015. Many people who live in Nepal's capital hail from districts outside the Kathmandu Valley and return home for the festival. (Photo by Navesh Chitrakar/Reuters)

A Chinese bus ushers jump as she pose for a photograph on Tiananmen Square during a plenary session of the National People's Congress held at the Great Hall of the People in Beijing, Wednesday, March 9, 2016. (Photo by Andy Wong/AP Photo)

People enjoy the fine weather on the coast at Wembury during the first ever nationwide survey to map the location of the threatened and creatures on March 24, 2011 in near Plymouth, England. Often found on the coast, and particularly in the south west of England, the number of oil beetle species found in the UK has halved in the last 100 years and the survey will help establish the whereabouts of the remaining four species and boost efforts to secure their future. The survey is being launched today by Buglife: The Invertebrate Trust and the National Trust in partnership with Natural England and Oxford University Museum of Natural History. (Photo by Matt Cardy/Getty Images)