Limestone structures inside Son Doong Cave. Photo credit: National Geographic
Son Doong has continuously won global attention since British cave experts first explored it 2009, with the help of local man Ho Khanh who discovered the cave in 1991.
The cave, which is five miles long, 450 feet at its widest and 600 feet at its highest, is not only known for its sheer size. There are shimmering rivers running through it, a dense subterranean jungle that keeps growing and fossilized corridors.
The Smithsonian magazine in August named Son Doong the greatest place to see in the 21st century.
ABC’s Zinger Zee called the cave "Avatar" as she came to make a Good Morning America episode last May. Bored Panda named it a place out of this world.