Nara Dreamland 1961-2006 (RIP). This is probably the largest abandoned theme park in Japan, that hasn't been razed to the ground. A victim of the Japanese economic bubble and the construction of Universal Studios in nearby Osaka.
Apparently there's a full-time guard in there that likes to fine people 700£. Luckily I didn't meet him.
Main Entrance
Main Street
The Aska Rolercoaster