Beneath the hill at Panorama Park runs a network of around 1.5 kilometres of Japanese-era tunnels, dug during the World War II occupation as a defensive bunker and headquarters. The visible section open to visitors includes ammunition stores, kitchens, sleeping quarters, an interrogation room, and dozens of access shafts that emerge into the canyon.
The tunnels are damp, low-ceilinged, and easy to get lost in without a guide; the official guides at the entrance are worth the small fee and have plenty of context to share. Bring a torch even though the tunnels are lit, and expect the visit to take about an hour.