No.2 SEA FORT (“No.2 Kaiho”) is one of the three man-made fort islands in Tokyo Bay that were built from the Meiji period (1868-1912) to the Taisho period (1912-1926).
No.2 SEA FORT was a giant facility with nine cannons on an area of about 41,000 m², and the cannons were interconnected by brick bunker rooms and passages.
A portion of this fort remains today, and since May, 2019, travel agencies have been offering various tours, allowing the public to visit.