Introduction to Sandan Pavilion: Legend has it that when Lao Tzu was meditating in Hangu Pass, a plague broke out in the local area. Lao Tzu used the bezoar spit out by the green bull he was riding to make pills and distributed them to the people, thus saving the local area from a disaster. (The story of Laojun refining alchemy stems from this). Later, people built the Sandan Pavilion to commemorate Laozi's saving of people by scattering pills.