The Son Doong Cave is GIGANTIC, and that may even be an understatement. It's actually the worlds largest cave. In 2009, a team of British cavers decided to investigate the Son Doong Cave. It's located in a remote area of the Vietnamese jungle, so preparing for the unknown was crucial. When they first started exploring the cave, they ran into a 46 foot high wall made of muddy calcite. They nicknamed this wall, The Great Wall of Vietnam. Well now these cavers have returned, and they are prepared to climb The Great Wall of Vietnam, explore what else may lay inside this cave, and to also see if this has the potential to be the new world-record holder for largest cave. The pictures they took while in the cave are amazing.