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 cafe-restaurant staff stands outside as people drink coffee in Monastiraki district of Athens, on Monday, May 25, 2020. Greece restarted regular ferry services to its islands Monday, and cafes and restaurants were also back open for business as the country accelerated efforts to salvage its tourism season. (Photo by Petros Giannakouris/AP Photo)

A boy holds a rifle as he sits at the site of a rally held by followers of the Shi'ite Houthi movement to commemorate the Ashura, the holiest day on the Shi'ite Muslim calendar, in Sanaa, Yemen on August 30, 2020. (Photo by Khaled Abdullah/Reuters)

A 20 metre high spiral staircase in a tower used as an emergency exit, is seen inside a Federal Reserve bank (Bundesbank) bunker, prior to the bunker's official opening to the public in Cochem, Germany, March 18, 2016. West Germany's Central Bank (Deutsche Bundesbank) stored some 20 billion German marks of emergency notes in two underground bunkers, one in Frankfurt the other in Cochem, between 1964-1988 during the cold war. (Photo by Kai Pfaffenbach/Reuters)

Brian Skerry can be called many things – explorer, journalist, conservation advocate – but he is first and foremost a photographer. His journeys to capture amazing underwater photographs have taken him across the world’s oceans. Photo: This Bahamian oceanic whitetip shark, known for the distinctive coloring on its white-tipped, rounded extremities, is part of a globally threatened species due to overfishing demands, primarily for its fins. (Photo by Brian Skerry)

Elephant fights off hyenas to save baby. “This is the incredible moment an elephant came to the rescue of one of its babies being attacked by a pack of hyenas. The elephant is seen charging at the hyenas to ward them off its offspring. The photos were captured by American photographer Jayesh Mehta, 47, in the Savuti region of the Chobe National Park in Botswana”. Photo: The elephant is seen charging at the hyenas to ward them off its offspring. (Photo by Jayesh Mehta/Caters News)

A blue tit comes face to face with its reflection in a car wing mirror in east Yorkshire in the last decade of July 2022. The photographer said: “I sat watching this little blue tit for 30 minutes as it fought with its own reflection”. (Photo by Dave Newman/Solent News)

Children play a game as Myanmar celebrates its 72nd Independence Day in Yangon on January 4, 2020. The country is celebrating the 72nd anniversary of its declaration of independence from British colonial rule. (Photo by Sai Aung Main/AFP Photo)