Rookery Entry Arch
Some say the building was named for the nest of crows that inhabited its walls, another story says that the squawking crows were symbolic of the corrupt officials who once inhabited the crumbling City Hall. The story I like is that the architect, upon hearing that the building might be renamed, had a pair of crows carved into the base of the arch in order to seal the name.
Frank Lloyd Wright covered all of John Root's original ironworks in The Rookery lobby with incised marble. When this detail was discovered during one of the renovations, it was decided to leave this column exposed on one side in order to show off the works of both architects (Root and Wright). Look for it as you enter, on the left hand side, the open side faces the wall.