Son Doong Cave, it noted, is the largest cave in the world. It was formed on a fault of the Truong Son Mountain Range and been eroded by groundwater over millions of years, which created a giant tunnel beneath the mountain’s limestone.  Son Doong Cave has the tallest stalagmites in the world, with giant stalactites over 80 metres in length and large pearls formed by drops of water falling from the ceiling over millions of years. Previously, on April 14, Son Doong Cave was promoted on the Google search homepage in 17 countries and territories./.