Yōrō lies at the foot of the mountains and is a popular momiji (autumn colours) viewing spot of central Japan. It is also the region chosen by the architectural duo Arakawa-Ginz to be first turned into their vision of the future.
Fall on your arse. No, seriously. Although part of a broader, unfinished vision for Yōrō, the existing Site of Reversible Destiny at Yōrō Park is for all intents and purposes a themepark where the theme is you, yes you, falling on your butt. Its sloped surfaces and utterly bizarre design is intended to disorient visitors. Try not to miss the pitch-black tunnel system on the northwest side: don't worry, theres no creepy crawlies living in there! The grand artistic vision is essentially that people rely on their physical senses too little and that peoples' lives can be made to revolve around navigating man-made objects (namely their houses). There are tonnes of books written on Arakawa-Ginz and their architecture and philosophies which make for interesting reading to say the least. These are the same crew that made the unusual apartments in Mitaka incidently. Even the website is a trip, be sure to read the directions for use. A short walk uphill from the train station. Admission 710 yen, gift shop stocks helmets.