Stretching over 250 kilometers beneath the jungle floor northwest of Ho Chi Minh City, the Cu Chi Tunnels are an extraordinary underground network that played a decisive role during the Vietnam War. Built over two decades starting in the late 1940s, this incredible subterranean system included living quarters, kitchens, weapons factories, hospitals, command centers, and even theaters — all connected by narrow passages just wide enough for a slim person to squeeze through. Today, visitors can crawl through widened sections of the original tunnels, gaining a visceral understanding of what life was like for the thousands of fighters and civilians who lived underground, sometimes for years at a time. Above ground, guides demonstrate the ingenious camouflaged trap doors, ventilation systems disguised as termite mounds, and the resourceful ways inhabitants survived against overwhelming military force.

Pro tip: Choose the Ben Duoc tunnel site over the more popular Ben Dinh site — it is farther from the city but significantly less crowded and offers a more authentic, less commercialized experience.