Vietnam’s Son Doong cave, the largest in the world, could hold a 40-story skyscraper inside. The pristine ecosystem has its own river and jungle. Despite its size, Son Doong wasn’t discovered until 1991. It was lost again for nearly two decades and was fully explored for the first time in 2009. (Photo by Jason Speth/HuffPost)

A displaced Pakistani girl collects recyclable goods from a garbage to earn living for her family in Islamabad, Pakistan, Tuesday, January 19, 2016. (Photo by B.K. Bangash/AP Photo)

Food is placed on the tomb of pet dog Xixi at Baifu pet cemetery ahead of the Qingming Festival on the outskirts of Beijing, China March 26, 2016. The Chinese characters on the gravestone read: “Mommy's only good son”. (Photo by Jason Lee/Reuters)

Members of the “Exit Point” amateur rope-jumping group jump from a 44-metre high (144-ft) waterpipe bridge in the Siberian Taiga area outside Krasnoyarsk, September 13, 2015. Rope-jumping, an extreme sport, involves jumping from a high point using an advanced leverage system combining mountaineering and rope safety equipment. (Photo by Ilya Naymushin/Reuters)

People look at lighting artist Bruce Munro's latest installation “Field of Light” is seen in the grounds of the Holbourne Musuem on November 23, 2011 in Bath, England. (Photo by Matt Cardy/Getty Images)

A clown nose is placed on a child's face during a protest opposing violence against women after the murder of Venezuelan actress and clown Julieta Inés Hernández Martínez in Rio de Janeiro, Brazil, Monday, January 8, 2024. The body of Hern·ndez, who had been missing since Dec. 23 while traveling by bicycle, was found in Presidente Figueiredo city, near Manaus in Amazonas state. (Photo by Bruna Prado/AP Photo)

A child plays with a mock submachine gun at a model Mass Transit Railway (MTR) station to mark the National Security Education Day at Hong Kong Police College in Hong Kong, China on April 15, 2021. The “education day” was organized to promote the sweeping legislation China imposed last year, marked with school activities, games and shows, and a parade by police and other services. (Photo by Tyrone Siu/Reuters)

Members of the Colombian Military forces pray for members of the military that have lost their lives and peace in the country at the Military Engineers School in Bogota, Colombia on October 14, 2021. (Photo by Juancho Torres/Anadolu Agency via Getty Images)