Lower Bay Station sits directly beneath Bay Station on the Bloor-Danforth subway line, built in 1966 as part of an ambitious but short-lived experiment to connect Toronto's two subway lines into a single through-running network. The idea was sensible in principle — trains from one line would continue onto the other, reducing transfers. In practice, the mixing of the two lines caused delays that cascaded through the entire system, and the experiment was abandoned after six months.
The station has been sealed since then, its platforms and signage left more or less as they were. The Transit Authority periodically opens it for public tours — typically once or twice a year as part of Doors Open Toronto or special TTC events. In the interim, it serves as a film set: because Toronto has stricter rules about filming on active stations, productions that need a period-appropriate or generic subway setting often use Lower Bay. It has appeared in numerous films and television shows as a stand-in for New York or Chicago stations.
Check the TTC website or Doors Open Toronto for the rare occasions when the public is allowed in.