ActiveCity

If you look at the east end of the platform on the tile walls, you'll notice there's an arrow that points towards 56 Street. They should reopen that exit honestly.

East of this station, there's an unbuilt 9th Street line that would have ended at Astor Place and Lafayette Street.

Not sure if this is true but, this station was built after the east river tunnel was completed and that's why the station has an odd shape to it.

The City Hall station has an unused lower level platform which can be used to terminate trains there, instead of the middle track at Whitehall St. That way, the R train can run from Rockaway Park-Beach 116 St to City Hall. Unfortunately, both of these plans may not happen anytime soon.