I know Venice is known for its canals, and they’re certainly something to behold, but this single rail tram-line blew me away.

A red tram approaching tram-stop with the track consisting of a single rail.

Edit: it occurred to me that these “trams” are running on regular tiers, and use this rail for the return current. That means they can get away with using just one overhead wire instead of two. I guess they can also use the rail for guiding the vehicle around curves as well? Seems like a bit of a disadvantage over other trolly-bus systems with trolly polls that can move around traffic.