Tāngdì Miào, a 600-year-old Taoist temple, is Guoyu's oldest building. It's well preserved with nine rooms and an operatic stage; the latter has Cultural Revolution–era paintings adorned with slogans exhorting the locals to work harder. Similarly, in the room on the left of the main worship hall, where you'll find a few disconcertingly life-like statues of deities, there are Communist propaganda slogans on the walls. The temple was a government building during the Cultural Revolution.
It’s also worth looking inside the former courtyard residence of Minister Chen’s grandfather at 1 Jingyang Beilu (景阳北路1号).
Admission here is included with the entrance to the walled village (郭峪古城, Guōyù Gǔchéng; ¥35).
