Such unimaginative answers
Here’s one that’s really on the rise
This is La Paz, Bolivia. In addition to being the highest altitude capital city in the world (3,640 m) it’s also got one of the worst topographies. It’s nearby suburb El Alto, sits 360 m above it. It’s densely packed with buildings and has horrible grades for large buses. It’s also built on solid rock so tunneling is difficult.
So, cable gondolas.
La Paz’s numerous gondola lines, called “telefericos” can carry 10 persons per car on nearly 1,400 cars. They can easily climb steep inclines. The support poles have a very small footprint, which means the system takes up very little space. Although 17 km/h doesn’t seem fast, it’s blazing in a city choked with traffic. Cars can leave a station as little as 12 seconds apart. The lines can thus handle somewhere between 2,000–4,000 people per direction per hour.
This sort of system is perfect for areas with numerous steep slopes, of which there are no shortage, particularly in the mountainous regions of northern South America like Venezuela and Columbia.