Abukumado Cave.

Stretching over 4,000 meters through 80-million-year-old limestone, Abukumado Cave offers a subterranean journey through three distinct levels, with a 600-meter section open to the public. The paved route winds through narrow passages and soaring chambers, highlighted by the massive Takine Goten hall. Along the way, dramatic lighting showcases an incredible variety of stalactites, stalagmites, and rare cave coral. The "Moonside" area features Japan’s first theatrical cave lighting system, shifting colors to create an otherworldly atmosphere. Visitors can opt for the standard path or pay a small fee to tackle the rugged exploration course, which involves crawling through tight crevices and climbing log ladders. It is a comfortable, year-round destination with a constant cool climate.