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 dark Devon Rex cat is held by its owner during a competition in Bucharest, Romania, Saturday, September 26, 2015. More than 300 cats entered the international feline beauty competition in the Romanian capital. (Photo by Vadim Ghirda/AP Photo)

A worker holds the head of a fox while killing it with electricity for its fur at a fox farm in Nanzhuang village, Shandong province, China, December 11, 2015. There are over 60 households in the village still raising foxes, raccoon dogs and other animals for the fur trade. China is the world's largest fur producer and exporter, according to state media. (Photo by William Hong/Reuters)

An Iranian girl walks at the Tochal ski resort, in north of Tehran, Iran on December 12, 2019. (Photo by Nazanin Tabatabaee/WANA via Reuters)

Revellers take part in the annual block party known as “Casa Comigo” (Marry Me), during carnival festivities in Sao Paulo, Brazil on February 15, 2020. (Photo by Rahel Patrasso/Reuters)

A girl attends Friday prayers in front of an army tank in Tahrir Square in Cairo February 18, 2011. Five years ago thousands of protesters took to the streets demanding the end of the 30-year reign of President Mubarak as Egypt became the second country to join the Arab Spring. After weeks of clashes, strikes and protests across Egypt, Mubarak resigned on February 11, 2011. (Photo by Suhaib Salem/Reuters)

Andrew Hepher, Vice President of Lubricants Technology, Shell unveils the Shell Concept Car in Beijing, China, Friday, April 22, 2016. Built as proof of energy efficiency that can be achieved with the latest technologies, Shell unveiled the concept car ahead of the bi-annual Beijing Auto Show where the world's top car manufacturers will showcase their own upcoming products. (Photo by Ng Han Guan/AP Photo)

Inside the new Digital Art Museum in Tokyo, Japan on June 21, 2018. These incredible photos show what it looks like inside a groundbreaking new digital art museum in Japan. A trip to the Mori Building Digital Art Museum: teamLab Borderless in Tokyo, which opened last week, can make you feel like they you are dreaming and aims to fully immerse visitors in the art. Spanning a spacious 10,000 square metres, 520 computers and 470 high-tech projectors create the illusion that the visitor is wandering through rice fields, following shoals of fish or even bouncing on a galaxy of planets. (Photo by South West News Service)