Akiyoshido is a famous limestone cave located in Yamaguchi Prefecture, Japan. It is part of the Akiyoshidai Quasi-National Park and is known for its impressive stalactites and stalagmites. The cave stretches over 10 kilometers, with about 1 kilometer open to the public for exploration. Discovered in 1920, Akiyoshido features a variety of unique rock formations and underground rivers. The cave maintains a constant temperature, making it a popular destination for tourists and researchers alike. Visitors can enjoy guided tours that highlight the cave's geological features and rich history.