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 Ballet Paraisópolis student wearing a face mask rehearses amidst the coronavirus (COVID-19) pandemic on August 13, 2020 in Sao Paulo, Brazil. The Ballet Paraisópolis is a project that teaches dance to children and young people in the Paraisópolis community in order to encourage them to seek better life opportunities. Founded in 2012 by ballerina, teacher and choreographer, Monica Tarragó, Ballet Paraisópolis has a total of 200 students and another 2,000 on the waiting list. (Photo by Alexandre Schneider/Getty Images)

The second of six C-17 Globemaster III airlifters for the United Arab Emirates Air Force and Air Defence is being assembled at the Boeing assembly facility on May 10, 2011 in Long Beach, California. The UAE will take delivery of three more C-17s this year and two in 2012 as it modernizes its airlift capabilities. (Photo by Kevork Djansezian/Getty Images)

Workers put some finishing touches on “Forever Marilyn”, a sculpture by Seward Johnson, on July 14, 2011 in Chicago, Illinois. The stainless steel and aluminum sculpture which stands 26 feet tall and weighs 34,000 pounds will be unveiled tomorrow and remain on display in Chicago through the spring of 2012. The sculpture was inspired by Marilyn Monroe's iconic scene in the 1955 movie “Seven Year Itch”. (Photo by Scott Olson/Getty Images)

Miss Venezuela Ivian Sarcos receives her Miss World 2012 sash from Miss World 2011 by Miss World 2010, Alexandria Mills (R) in the Miss world 2011 World Final on November 6, 2011 in London, England. (Photo by Jeremy O'Donnell/Getty Images)

A performer poses with “The Gronkle” and “Deadly Nadder” at the How to Train Your Dragon Media Call at Fox Studios on November 29, 2011 in Sydney, Australia. The “How to Train Your Dragon Arena Spectacular” world premiere will take place in Australia in March 2012. (Photo by Brendon Thorne/Getty Images)

The under-construction Shard building on December 5, 2011 in London, England. The 80 storey skyscraper will be Europe's tallest mixed-use building when it is completed in May 2012; it will contain offices, restaurants, residential apartments as well as a five star hotel. (Photo by Dan Kitwood/Getty Images)

Hardy Dutch swimmers brave the icy North Sea on January 1, 2012 in Scheveningen, Netherlands. A record number of 10,000 people took the plunge in this year's traditional New Year's dip. The high turnout was attributed to the mild weather with a sea temperature of 8 degrees compared to 4 degrees last year. (Photo by Jasper Juinen/Getty Images)