Back in 1884 a guy named Thompson invented the roller coaster called the Switchback Railway. This roller coaster went 9 miles per hour and was a nickel to ride. The roller coaster like where the people sit was 50 feet long and it was a 600 foot high platform that they would go down from.
Today the roller coasters are way better and faster. The roller called the x2 is in California and has a fifty story drop so that is 400 feet tall. The ride to make it cost $10 million and the x2 hurt 1,800 people.