Tianchi Peak, the second highest peak of Tianzhushan, named after Tianchi (the heavenly pools) on the peak, is a granite inselberg or mountain-island. The boulder on the top of the peak is split by an East-West joint to form two cracks. The slab on the boulder is called “courage-challenging bridge”, also known as “immortal bridge”, because there is an old saying that “those who are lucky enough to cross the bridge are considered immortal”. The cliff beside the heavenly pool is so precipitous that it is called “mind-testing cliff”.Legend has it that all Taoists must have their minds tested at the cliff before practicing Taoism in earnest.

 1.Pits are formed when the minerals on the granite surface peeled off

2.The pits suffer water, wind erosion and frost wedging.

3.The pits become deeper and bigger

4.The pits suffer water, wind erosion and frost wedging again.

5.Two oval pits are formed.