Vietnam | Discovered by Ho Khanh in 1990, Hang Son Doong has emerged as the world’s largest cave both by volume and by cross section, making for a breathtaking view from the cavern’s mouth. The cave is home to 230ft stalagmites and entire forests of trees, grown beneath massive openings in the cave’s ceiling. Nearby in the same Phong Nha-Kẻ Bàng National Park is Hang En, the world's third-largest cave. Some tour groups offer the chance to camp inside.
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