One of the main tourist attractions near Kunming is the Stone Forest (Shi lin). It's a karst landscape of towers that were created donkey years (OK, estimated at about 250 million years) ago and continue to stand (mostly -- some have fallen over during earthquakes).

Karst formations are found pretty widely around Southeast Asia & Oceania. As I understand it, karst is basically what happens when acidic water (rain + CO2 or acidic soil) dissolves limestone rock... over long, long periods of time. This seems to usually happen underground, but in the case of the Stone Forest, all of the water has receded, so the Forest stands dry. Karst makes a reapparance, in slightly different form, later in the trip, so hang onto that little nugget until it comes in handy again.