A 1966 aerial map of Odaiba when it was used as a ’kiba’ 木場, a floating lumber storage area. The stone structures are the old ‘daiba’ defensive islands that were built in the 19th century to protect against Western invasion.
Much later, post WW2, this area of Tokyo underwent massive land reclamation. As seen in this photo, by 1966 the land reclamation project was already underway, and the reclaimed land starts to become visible. See: Odaiba, then & now: a visual history お台場の歴史