Mikawa Mu Valley Underground Kingdom

A theme park built on the former site of a tungsten mine in the mountains of Iwakuni, Yamaguchi Prefecture, along the Nekasa River. Visitors can enjoy an adventure through a space said to have been discovered during the mine’s operation, stretching for Approx. 1 km. The underground space stays at Approx. 18°C year-round, cool in summer and warm in winter.

Inside the Underground Kingdom, giant murals and stone statues are scattered throughout. All of them are inspired by an ancient civilization, creating a mysterious atmosphere unique to the underground setting. The illuminated underground lake and underground waterfall, glowing with a dreamlike beauty, are also not to be missed. You can also take on a puzzle-solving attraction where you visit each point and aim to escape from the Underground Kingdom.

The gold panning and gemstone hunting experience area near the entrance to the Underground Kingdom is especially popular with children. You can take home the gold and gemstones you find within the time limit. There is also a restaurant known for its curry topped with pyramid-shaped rice that looks great in photos, as well as bathing facilities and accommodations where you can refresh yourself after a day of fun.