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 B-52 bomber is watched by a group of curious onlookers as it lands at RAF Fairford, February 21, 1999. The B52s arrived from the U.S.A. as part of NATO's preparations for air attacks on Yugoslavia as tensions in the Kosovo crisis increased. (Photo by Dylan Martinez/Reuters)

7th August 1941: A Soviet sniper targets the enemy with the telescopic sight on his rifle.

In this Thursday, February 9, 2017 photo, a Bangladeshi boy pulls a rickshaw loaded with strips of leather at the highly polluted Hazaribagh tannery area in Dhaka, Bangladesh. Hazardous, heavily polluting tanneries with workers as young as 14 supplied leather to companies that make shoes and handbags for Western brands, a nonprofit group that investigates supply chains says. (Photo by A.M. Ahad/AP Photo)

Rio Takahashi of Japan gets ready for the final show of the Miss International Queen 2020 transgender beauty pageant in Pattaya, Thailand on March 7, 2020. (Photo by Soe Zeya Tun/Reuters)

A photographer has weathered some of Americas most violent storms to capture these stunning snaps. Storm chaser Mike Mezeul II, 30, has travelled all over the US to shoot the likes of mammoth thunderstorms and surreal cloud patterns. His incredible collection of storm images are the result of more than 15 years of photography and thousands of miles of travel. The photographer, from Frisco in Texas, USA, became interested in storm chasing aged 16 when he got his first car. He has since shot ferocious storms as far north as the Canadian border and as far south as Mexico. (Photo by Caters News)

Monaco's Princess Charlotte Casiraghi arrives to attend a mass at the Saint Nicholas Cathedral during the celebrations marking Monaco's National Day, on November 19, 2016 in Monaco. (Photo by Valery Hache/Reuters)

The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on July 21 as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, located 62 feet below the surface of the Atlantic Ocean in the Florida Keys National Marine Sanctuary. The NEEMO 21 crew will perform research both inside and outside the habitat during a 16-day simulated space mission. During simulated spacewalks carried out underwater, they will evaluate tools and mission operation techniques that could be used in future space missions, including journeys to Mars. (Photo by Karl Shreeves/NASA)