Roller Coasters started to get popular around the 16-17th century. In Russia they used huge ice slides and the passengers would clash-land into sand piles the technique was based on friction. Later on wooden sleds with iron runners were introduced to gain more speed. The first american amusement park was introduced to Coney Island in 1875. In 1884 the first gravity switchback train was introduced. In 1912 the first underfriction roller coaster was introduced. The design held the train in and it allowed more speed, steeper hills, and less drag. The Great Depression and World War 2 caused a decline in parks. In 1955 the nation’s first theme park opened it was DisneyLand. Not only did it usher a new era of amusement park it also changed the way
