Rollercoasters have many types. The basic types are wood coasters, and steel coasters. Wood made of wood. Steel made of steel, of course. But as the popularity of coasters grew, and technological advancements were made, new kinds of coasters were introduced, from Inverted coasters, to Stand-Up coasters. However, most new coaster types aren't made of wood, because wood isn't strong enough to carry the trains required to stay on the track. Eventually, water rides were also added to the mix. These coasters weren't like waterslides, but coasters with a track or a barrier that only lets the "boat" go in a specific direction. Rides like Kali River Rapids at Walt Disney World have these barriers, which is why sometimes while on the ride, you feel the raft stop and spin a bit. One of the most unique water rides operates in South Korea, with a track like a regular roller coaster, including it's very own launch! Other ride types like the Bobsled type are being abandoned because they are too dangerous, and aren't attracting enough guests. Less then 10 bobsled coasters are in operation in the world, 2 of which are in America.

Below: Batman the Ride featured in multiple Six Flags Amusement Parks are an example of an Inverted Roller Coaster

Below: Mattehorn Bobsleds is a popular and old attraction at Disneyland in California!