Inside the world's largest cave This is the world's largest cave. Picture: Ryan Deboodt Source: Supplied A stunning example of cave pearls. IT'S big enough to hold towering jungles, white sandy beaches, its own weather system and animals that can't be found anywhere else in the world. But until recently the hidden treasures of the world's biggest cave were a mystery to the rest of the planet. Explorers have only started venturing into Vietnam's Son Doong cave over the past few years and they've come out the other side with tales of a sprawling, untouched world. And finally, thrillseeking tourists are joining them. "The place humbled me and reminded me of how insignificant we really are - there are stalagmites like skyscrapers, jungles, strange animals that no one has even seen before," Ben Mitchell, the first Australian to explore the cave, said of the experience. The Son Doong was discovered by a local jungle man in the early 1990s, but the steep drop into the mouth of the cave scared locals away. According to lore, the jungle men were afraid of the cave because of the shrill whistling sound made by its fast-flowing underground river. Camping inside the cave. The entrance was lost in the jungle growth for nearly two decades until a British expedition blazed a trail in recent years. It's impressive. Nestled in the wild and remote jungles of the Phong Nha Ke Bang National Park, the Son Doong cave is so big that even the narrower chambers would be able to fit a 40-storey CBD block. There's a towering jungle inside. Sunshine streams into the cave through two collapsed roofs, allowing lush and green jungles to thrive. In pictures: Incredible glacier caves Hotel being built inside abandoned quarry In other parts, giant stalagmites climb a staggering 80 metres into the sky and the cave contains some of the world's most dazzling examples of cave pearls. Explorers inside the cave. Picture: Bart Jellema Source: Supplied Explorers recently found fossils, believed to be 300 million years old, in a newly discovered passage. The cave is so vast, it even has clouds rolling through it. And the brilliant variety of plant life is matched by the wild array of animals, with monkeys, hornbills and flying foxes all spotted by travellers. Plants reaching towards the sunlight. Aussie adventurer Luke Ford visited Son Doong on holiday but was so moved by the trip that he threw in his Melbourne office job and returned to work for the tour company who operates the trips, Oxalis. He was dumbfounded by the unforgettable sights of his first journey. Luke inside the cave. "As we crossed the underground river for the second time, clambering over massive boulders past the Hand of Dog, we came across a view that left us all absolutely speechless," Ford recalled of his recent visit. Sunshine and cloud poured through the collapsed part of the roof, lighting up gigantic 200-metre cliffs and our little campsite resting on a sandy plateau overlooking the first jungle section of the cave. Small tour operators have government approval to guide travellers through the Son Doong cave. The first group trekked through in August. More information here. Tours have recently begun.