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)

In this photo taken on Saturday, April, 4, 2015, a bear chews on a corncob at a shelter that attracts hundreds of visitors and volunteers from around the world every year, in Kutarevo, Croatia. Over a decade ago, Ivan Crnkovic-Pavenka, a retired Croatian social worker decided to help bears become “ambassadors of the wilderness” among people and set up a unique shelter for brown bears in the idyllic mountain village of Kutarevo in central Croatia, where eight bears currently live in two huge enclosures. (Photo by Amel Emric/AP Photo)

Competitors perform at the World Irish Dance Championship on April 13, 2014 in London, England. The 44th World Irish Dance Championship is currently running at London's Hilton London Metropole hotel, and will host approximately 5,000 dancers competing in solo, Ceili, modern figure choreography and dance drama categories during the week long event. (Photo by Dan Kitwood/Getty Images)

Bodybuilders pose on stage during the Mr.001 bodybuilding competition in Mombasa, Kenya, on December 11, 2021. This bodybuilding competition was created by a former bodybuilder and its the first one to happen in the coastal city since 2015. The name comes from Mombasa's county code and currently is considered one of the biggest in East and Central Africa. The first edition brought over 200 participants from Kenya, Uganda, Tanzania, Nigeria, South Africa and Pakistan who competed in different categories including physique, bikini and figure. (Photo by Patrick Meinhardt/AFP Photo)

Men wear masks as they sit in the metro in Prague, Czech Republic, 17 March 2020. According to media reports, the Czech government decided to impose a two-week quarantine in the country on the evening of 15 March, and ban all international travel from 16 March 2020. Currently 383 cases of the coronavirus SARS-CoV-2, which causes the Covid-19 disease, have been officially confirmed in Czech Republic. (Photo by Martin Divisek/EPA/EFE)

A pedestrian wearing a form of PPE (personal protective equipment) of a perspex full-face covering, as a precautionary measure against COVID-19, walks across Oxford Street in central London on June 11, 2020, as non-essential shops prepare to re-open on June 15. Britain's current guidelines on social distancing remain at two metres (2M), but business leaders and some politicians are on Thursday calling for it to be reduced to one (1M), or one-and-a-half (1.5M) metres. (Photo by Justin Tallis/AFP Photo)

In this October 6, 1976, file photo, a right-wing student, center foreground, draws his arm back to strike a captured and wounded leftist student being taken by police to an ambulance in during a student massacre in Bangkok, Thailand. This year’s anti-government protests are seeking new elections, a more democratic constitution and an end to intimidation of political activists. Their speeches have repeatedly highlighted the 1976 tragedy, piquing the interest of the current generation in what their forebears faced. (Photo by Neal Ulevich/AP Photo/File)

An anti-lockdown activist dressed as Father Christmas is arrested in Grosvenor Square during a demonstration in London, England, on November 28, 2020. London is to return to “Tier 2” or “high alert” covid-19 restrictions once the current England-wide coronavirus lockdown ends next Wednesday. All three of the tiers, assigned to local authorities across England, have been strengthened since the lockdown began on November 5, however, with the main impacts to be felt by the hospitality sector. (Photo by Mark Thomas/i-Images)