No trying to advocate the devil, but Kremlin is trianle-like shaped, there's river from one side with bridges at the ends (so it could be counted as a tunnel),

No trying to advocate the devil, but Kremlin is trianle-like shaped, there's river from one side with bridges at the ends (so it could be counted as a tunnel), Red Square from another (pedestrian only unless you're a member of Victory Parade, one-way streets aside), the third side is surrounded by Mokhovaya street which has 5 intersections with others and you can get to the one you'd want if you've skipped your turn.