I came across a type of transportation I'd never seen before in Istanbul called a funicular. The concept is simple: It's basically an elevator with a counterweight, except that instead of an elevator with a counterweight it's two equally sized cars on rails going up/down a steep hill. The cars are connected by a single cable, and at the top of the hill there's a very large wheel that hoists them back and forth. It's not used in many places, since you can only have two cars (one up, one down) and that usually only means two stops. Moreover, it's only efficient on very steep hills, so they don't show up in many large cities.
That being said, the funicular in Istanbul was by far the best part of their public transit system. It cost about $1.30 to ride it one stop, and it was worth every penny.