Son Doong Cave

"Caves are fragile environments. They don't regenerate very quickly, and once they're broken, they're broken."
Unless you've been under a travel rock for the past couple of years, you've probably heard about the discovery of Hang Sơn Đoòng (HSD), the largest cave in the world. The good news? It's now open to explorers.
But nobody knew any of that until about six years ago. Son Doong is a jackpot of rare cave pearls. The pearls form over hundreds