Pristine rivers and the soaring karst peaks of Guilin and Yangshuo in the north draw more than a million Chinese tourists each year.

Deciduous and evergreen forests dominate the limestone karst formations of the northwestern highlands of Thailand.

Their formation is most common in easily erodible karst terrains with carbonate rocks, like limestone or dolomite, or minerals known as evaporites, like salt and gypsum.

The karst lands are so embedded in our cultural sense of place, we’ve got our own map of chthonic legends.

Turkey’s landscape is marked by karst, a type of terrain where caves easily form.