Children and grown-ups are doing it. Skiers and ice hockey players are doing it. Athletes and acrobats are doing it. What is "it"? In-line skating! In-line roller skates are more and more popular. Millions of people in Europe and the USA are putting on their skates and doing the strangest things. Ice-hockey players and skiers use them in summer. Some have stopped playing ice hockey and play roller hockey with in-line skates instead. Why? It's more fun! Roller hockey combines elements of hockey and basketball. Even women play in-line roller hockey. The streets of America are full of children playing hockey on their skates. In London parks there are now special skating sections so that skaters don't frighten joggers and walkers when they whizz past at 50 kilometres per hour!' Of course, some people like competition, so there are in-line speed-skating championships with different distances. Joseph Merlin, a Belgian inventor and musical instrument maker, invented the roller skates in about 1760. He was also the first person to wear them. He wore his ' new metal skates to a party in London, where he crashed into a very expensive mirror. He wasn't very interested in skating after this experience. In 1863, James Plimpton, an American businessman, invented a roller skate that could turn. Plimpton opened a skating club in New York where gentlemen enjoyed showing off for the ladies by doing fancy figures, steps and turns. Within 20 years, roller skating had become a popular pastime for men and women. Indoors, wealthy gentlemen played "roller polo," a hockey game. Others held contests in dance and figure skating. Outdoors, men and women were racing in speed contests. The more the public saw of skating, the more they wanted to try it themselves. Roller skating was soon enjoying its first boom. Roller hockey teams were playing throughout Europe as early as 1901. In the 1970s, the first plastic skate wheels were made. Such wheels were quieter than those made of wood or metal, and skaters could move faster and easier. In 1980s, a new kind of roller skates appeared. They are called in-line roller skates. They were invented by two brothers in Mnnesota, USA, who wanted to practice ice-hockey in the summer. Everybody liked the invention and soon the two brothers started to produce in-line skates commercially. In 1984, Rollerblade, the first in-line skate company was bom. Today, there are lots of companies and lots of skates.