The Son Doong cave, at over 5.5 miles long and big enough to fit a 40-story skyscraper inside its walls, making it the world's largest cave, is being opened to the public for the first time, according to FOX News.

A tour company called Oxalis is currently running trial tours of the cave and has started taking names to sign-up for six-day tours that will be held starting next year. Visitors on the tour will enter the cave by rappelling down 80 meters.

The tours will take visitors through the cavernous space during the day and have them sleeping on the sandy beaches inside it at night. The tour schedules the first night at Hand of Dog, a giant stalagmite that resembles a dog's paw.

A local man first discovered the cave, located in Vietnam, in 1991. However, the entrance he found had too steep of a drop to enter. The cave then remained unexplored for 18 years. It was only four years ago, in 2009, when two British cave explorers went into the cave and brought attention to what is now known as the largest cave on earth.

The roof of the cave collapsed centuries ago, allowing a jungle, known as the Garden of Edam, to grow and thrive. The jungle holds flying foxes, monkeys and hornbills. The cave also contains stalactites and waterfalls, as well as a river.

There are also two underground sinkholes that have cliffs as high as 800 feet, as well as one known as the "Great Wall of Vietnam" that is over 15 stories high. Parts of the interior stone are covered in fields of algae and some of the walls contain rare pearls of calcite crystals.

To book a tour, visit the Oxalis website. The cost is $3,000 and includes a week inside the cave. The 2014 tour will only accommodate 220 tourists, so it's important to book as far in advance as possible.

Video of the cave tour.