About 4,000 years ago, humans started drawing geometric patterns, animal and human figures on several grottoes. These are the most ancient signs of civilization in this area. There are also stone markers sculpted about 1,200 years ago by the Mon Dvaravati people, and they can be found around the most audacious rock balancing acts. It was around this time that statues of the Buddha were carved into niches, but nearly all of these were destroyed by invaders.