A merry-go-round works through a motor that powers the rotation of a platform on a set of rollers that rotate around a stationary pole. Gears on the pole connect to gears on the support beams and the platform, which cause the platform to rotate.
The horses that move up and down are connected to cranking rods suspended from the ceiling of the merry-go-round. Pulleys on the cranking rods are connected to gears that move them in a circular motion. The horses hang from the cranking rods, and as they turn in a circle the horses move up and down. The average horse goes up and down 30 times per minute.
Modern merry-go-rounds evolved from early jousting traditions that involved the knights going around in a circle. They were originally made of wood and powered by humans, mules or horses. Horses are the most common animals featured in the rides, but other animals have been added over the years. They were a popular carnival ride, especially in the 1800s, until interest in carnivals and amusement parks died out after the Great Depression in the 1930s. After the 1970s, there was a movement of people who wanted to restore merry-go-rounds and preserve the original ones, and some sites have been declared heritage sites.