Introduction to the Deer Drinking Trough: On the flat land west of Yuan Pavilion today, there is a large stone trough 300 cm long, 92 cm wide and 56 cm high. It is said that it was a place where reindeer drank water in the Tang Dynasty. Lao Tzu's mount is an immortal deer. According to this theory, it may be the stone trough where Lao Tzu drank from the deer, or it may have been built by later generations to follow the legend.