#73 Vietnam – Ha Long Bay
Ha Long Bay, the “bay of the descending dragon,” always surprises visitors for its sheer scale. Not just in the size of the limestone karsts, but the sheer number of them, around 2,000 over an area of more than 1,500 square kilometers.
The limestone took 500 million years to form, while the bay itself is 20 million years in the making, thanks to the tropical climate wearing away the rocks and allowing a biosystem of caves, inlets and greenery to thrive. Not to mention human culture for tens of thousands of years.