冢下有一神秘地宫,内有一盏万年灯,常年不熄。亲历者中庙村邢姓老人为地宫内的万年灯送油,曾顺墓道进入地宫。
Located in the northeastern corner of Emperor Yan’s grave scenic, it is north to Ping, south to balcony Dan water, and west to Yangshan. The circular stone structure of the grave has a diameter of 15 meters, more than five meters height, and 3.15 meters high stonewall inside where the sarcophagus was built. Stand before the graves stone shrine, its interior is a national treasure. The stone monument has a height of 0.95 meters, a width of 0.66 meters, and was built in thirty-nine orthodoxy by the legislature, which is the earliest discovered Emperor Yan monument.
There is a mysterious underground palace under the temple with a perennial light. An elderly witness named Xing from the nearby village once sent the oil to refill the oil light for the underground palace through a tunnel in the grave.