This network of defence tunnels stretching underground for 10km, are estimated to be 1400 years old and believed to be the longest of their kind in China. Troops were stationed here in the Sui and Tang dynasties but they were never used. Today, 1500m of tunnels on three levels have been restored. You descend as low as 26m in places and tour narrow and low passages, which were once guardhouses, bedrooms, stables and ambush spots. Older children might like the adventure.
Near the entrance to the maze is a Kehan Temple, dedicated to the leader of a northern nomadic tribe. His likeness is golden and looks formidable with bulging eyes. Go to the roof of the temple for a bird's eye view of the village.
Zhāngbì Cūn (张壁村) is a still-occupied Yuan-dynasty farming village above the tunnels. It is quite picturesque, but there was a lot of construction underway at the time of research. You can wander its cobblestone streets, cave dwellings and temples for free.
You can only get here on tour or by private car (per day ¥380). Check with your accommodation in Pingyao.