Oya History Museum

The Oya History Museum (大谷資料館, Ōya Shiryōkan) is a museum built inside a massive former stone quarry northwest of central Utsunomiya. The man-made caverns were originally developed during the Edo Period to mine Oya Stone, a soft, yet durable volcanic stone that is only found locally. Oya stone has been used over the centuries as a building material, and has been utilized in famous structures such as the facade of the former Imperial Hotel in Tokyo.

Evidence of mining can be seen all around the area, with huge slices taken out of the hillsides and giant voids carved into the mountains. The underground mines remained in operation until 1986, and by then an enormous series of caverns had been carved into the ground. A building sits at the entrance to the mines and houses a small museum that explains the history of the area and exhibits different mining tools used to excavate the rock over the centuries.

From there, visitors can descend into the museum's extensive underground halls which cover over 20,000 square meters and are more voluminous than Tokyo Dome. A large section of the excavations is open to explore, and you may want to bring a jacket as the man-made caves act as a natural air conditioner with an average temperature of around ten degrees Celsius.

Many of the halls are lit up with colorful lights and house art installations, while others have been outfitted to serve special purposes, including a room with a chapel and one with a stage cut directly out of the rock. The surreal mines are frequently used as event space. They have also served as venues for concerts, weddings, art exhibitions and shooting location for various commercials and music videos. A gallery exhibits photographs from many of these events.