The small town of Yoshimi, Saitama, is known mostly for the Hundred Caves, the largest grave cluster in Japan. A few minutes away from the caves, however, lies another strange cave that was once just as popular.

Gankutsu Hotel ("cave hotel") is a strange structure dug out of a sandstone cliff overlooking the Ichino River. It's enclosed by fences today and unauthorized entry is prohibited as it is private property. 

It was constructed by Minekichi Takahashi, a local strawberry farmer, who wanted to make a sake brewery and cellar out of the cliff. A self-taught architect with no professional experience, Takahashi chiseled the rocky hill purely for his artistic satisfaction and kept on working from 1904 to 1925 until he passed. After his death, his son took over the work, and by the 1920s, it had become a major tourist spot in the area. Even The London Times published an article about the work of art. 

During the Pacific War, the site was closed down and a new tunnel was dug to make a factory for the military, connecting the site with the Yoshimi Hundred Caves and the nearby Matsuyama Castle. After the war, the site's popularity returned and many people came to visit. However, typhoons did considerable damage to the site in 1982 and 1987, soon after which Takahashi's son died. That made it impossible for the site to reopen and it has been closed ever since. It's now a popular spot among haikyo aficionados and ghost hunters, who claim that restless spirits haunt the second-floor windows.

Despite its name, Gankutsu Hotel was never actually meant to be a hotel. Its name comes from the local comments on Takahashi's construction, "gankutsu hotteru," meaning "he's digging the caves." Hotteru was confused with the word hoteru, which is how the Japanese pronounce "hotel," and the name simply stuck at some point.