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 South Korean model poses with Peugeot 5008GT during a press preview of the Seoul Motor Show in Goyang, northwest of Seoul, on March 30, 2017. South Korea's largest international auto show will open on March 31, with a total of 27 brands showing their latest cars and concepts. (Photo by Jung Yeon-Je/AFP Photo)

Jess Lockwood, of Volberg, Mont., is bucked off Johnny Gringo during bull riding rodeo finals at the Calgary Stampede in Calgary, Alberta, Sunday, July 16, 2017. (Photo by Jeff McIntosh/The Canadian Press via AP Photo)

The “EMIEW3” robot (R) demonstrates communicating with a visitor during a press preview in Tokyo on April 8, 2016. Japanese electronics giant Hitachi unveiled its humanoid customer service and guidance robot “EMIEW3” and “remote brain” robotics IT platform. (Photo by Toshifumi Kitamura/AFP Photo)

More than 1,500 snappers submitted their most hilarious pictures of all creatures great and small, and now 45 have made the cut. From drunken-eyed owls to embarrassed chipmunks and laughing goats – the finalists in the Comedy Wildlife Photography Awards are guaranteed to raise a smile. Here: 'Dancing sifaka'. (Photo by Alison Buttigieg/Comedy Wildlife Photography Awards/Mercury Press)

Frog legs it! Indonesian flying frog tries to hitch a ride on snail's back before realising it would be quicker to hop it alone. A tiny frog struck up an unlikely friendship with a giant African land snail after clambering onto its shell to catch a ride. (Photo by Hendy Mp/SOLENT/Visual Press Agency)

Newborn orangutan Rieke is presented during a press conference at Berlin Zoo, in Berlin, Germany, February 6, 2015. The baby was born on January 12, 2015 weighing 2,290 grams and is bottle-fed by keepers. (Photo by Ralf Hirschberger/EPA)

These two ladies received some important messages on Valentine's night in Manchester, England on February 14, 2020. Brits celebrated Valentine's Day in style last night – proving you can have a good time even if you don't have a partner. (Photo by Mercury Press/The Sun)