Mermaid Theatre
City of London, United Kingdom · built 1959
The Mermaid Theatre was a theatre encompassing the site of Puddle Dock and Curriers' Alley at Blackfriars in the City of London, and the first built in the City since the time of Shakespeare. It was one of the first new theatres to abandon the traditional stage layout; instead of this, a single tier of seats surrounded the stage on three sides.
Venue data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).