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)

Anti-bullfighting demonstrators protest against the bulls runs, while standing in cardboard coffins and holding red flowers, on the Ayuntamiento Square in Pamplona northern Spain on Friday July 5, 2013. On July 6, the San Fermin festival will begin with the “txupinazo” , the opening ceremony with people participating in bull runs, music and dance, through the old street of the city. (Photo by Alvaro Barrientos/AP Photo)

In this November 11, 2017 photo, children dressed in traditional outfits play during the Azorean Culture Festival which celebrates the culture of the Azores, the Portuguese island chain in the mid-Atlantic, in Enseada de Brito, in Brazil's Santa Catarina southern state. “We have to make sure that our culture always stays alive, not let it die”, said Andre Cordeiro, who leads one of the singing and dancing groups that performed this year. “We are able to pass it on from generation to generation”. (Photo by Eraldo Peres/AP Photo)

A picture made available on 13 May 2016 shows A Tiwa girl performing her traditional dance as they celebrated the Wanchuwa festival in Karbi Anglong District of Assam state, India, 11 May 2016. Wanchuwa is one of the most important festivals of the Tiwa tribal community living in the hills as it is related with agriculture which is the mainstay of their economy. Tiwas pray for a bountiful harvest during this festival and to protect their crops from pest and other natural calamities. Tiwa is a major tribe of Assam state who practice Jhum or shifting cultivation for their living in the hills. (Photo by EPA/Stringer)

Samburu women of the Lorubai traditional dance group are seen wearing traditional beaded necklaces during a Peace Marathon for pastoralist communities at the Archers post in Isiolo, Kenya on April 26, 2018. The aim of the event is to bring the warring pastoralist communities of Samburu, Turkana, Borana and others together, and end the rivalry due to scarcity of pasture and water in the region. The peace marathon is organized by Kenya's Northern Rangeland Trust. (Photo by Simon Maina/AFP Photo)

A member of the Qinghai Acrobatic Troupe checks her hair with a smartphone during a media preview for the world premiere of cabaret show “Shanghai Mimi” as part of Sydney Festival in Chinatown, central Sydney, Australia, 08 January 2019. Sydney Festival 2019 runs from 09 to 27 January and will feature theatre, dance, circus, music, visual arts and talks from international and local artists. (Photo by Steven Saphore/EPA/EFE)

Francisco Solano poses for a photo in his bird-feather suit after attending a Mass commemorating the feast day of St. Francis Solano, in Emboscada, Paraguay, Friday, July 24, 2015. Some 500 people attended the festivity – a mix of indigenous and Guarani Indian beliefs. The festival begins with a Mass, continues with a procession of the diminutive wooden statue of St. Francis, and ends with people dancing in suits made with black, white, brown and grey feathers. (Photo by Jorge Saenz/AP Photo)

Tlingit Tribal members from Klawock, Alaska Eva Rowan, center, and Jonathan Rowan, right, watch Okolani Tallett perform a hula dance at the Honolulu Museum of Arts, Thursday, October 22, 2015, in Honolulu. A totem pole, stolen by actor John Barrymore during a sailing trip to Alaska in 1931, was returned to the Tribe today by the Honolulu Museum of Arts where it was on display since the early 1980s. The totem pole was carved by the ancestors of the Tlingit Tribe. (Photo by Marco Garcia/AP Photo)