A prison in central Tokyo known for housing some of the country's most infamous criminals, this place fascinates the dark tourists of Tokyo. A grey and grim structure with its own execution rooms, the detention house can be viewed well from the Tobu Skytree line if you know where (and when) to look. The leader of the Aum Shinrikyo cult (responsible for the sarin poison attacks of 1995) was held an executed here and the most recent big name was Carlos Ghosn (of the motor-industry drama) so it is certainly a high-profile prisoner spot. Unusually, they hold an annual festival in Summer selling items made by prisoners and offering a chance to try prison curry.