This mad rollercoaster looks really dangerous.

Amusement park is the generic term for a collection of rides and other entertainment attractions assembled for the purpose of entertaining a large group of people. An amusement park is more elaborate than a simple city park or playground, usually providing attractions meant to cater to adults, teenagers, and small children. A theme park is a type of amusement park which has been built around one or more themes, such as an American West theme, or Atlantis. Today, the terms amusement parks and theme parks are often used interchangeably.

Statistically, roller coasters are very safe. The U.S. Consumer Product Safety Commission estimates that 134 park guests required hospitalization in 2001 and that fatalities related to amusement rides average two per year. According to a study commissioned by Six Flags, 319 million people visited parks in 2001. The study concluded that a visitor has a one in one-and-a-half billion chance of being fatally injured…

A bicycle, also known as a bike, pushbike or cycle, is a pedal-driven, human-powered, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist or a bicyclist.Bicycles were introduced in the 19th century and now number about one billion worldwide, twice as many as automobiles. They are the principal means of transportation in many regions. They also provide a popular form of recreation, and have been adapted for such uses as children’s toys, adult fitness, military and police applications, courier services and bicycle racing.The basic shape and configuration of a typical upright bicycle has changed little since the first chain-driven model was developed around 1885. However, many details have been improved, especially since the advent of modern materials and computer-aided design. These have allowed for a proliferation of specialized designs for particular types of cycling.

The invention of the bicycle has had an enormous impact on society, both in terms of culture and of advancing modern industrial methods. Several components that eventually played a key role in the development of the automobile were originally invented for the bicycle – e.g., ball bearings, pneumatic tires, chain-driven sprockets, spoke-tensioned wheels, etc.

History
Multiple innovators contributed to the history of the bicycle by developing precursor human-powered vehicles. The documented ancestors of today’s modern bicycle were known as draisines, hobby horses, or push bikes (and modern bicycles are sometimes still called push bikes outside of North America). Being the first human means of transport to make use of the two-wheeler principle, the draizine (or Laufmaschine, “running machine”), invented by the German Baron Karl von Drais, is regarded as the forerunner of the modern bicycle. It was introduced by Drais to the public in Mannheim in summer 1817 and in Paris in 1818. Its rider sat astride a wooden frame supported by two in-line wheels and pushed the vehicle along with his/her feet while steering the front wheel.

In the early 1860s, Frenchmen Pierre Michaux and Pierre Lallement took bicycle design in a new direction by adding a mechanical crank drive with pedals on an enlarged front wheel (the velocipede). Another French inventor by the name of Douglas Grasso had a failed prototype of Pierre Lallement’s bicycle several years earlier. Several inventions followed using rear wheel drive, the best known being the rod-driven velocipede by Scotsman Thomas McCall in 1869. The French creation, made of iron and wood, developed into the “penny-farthing” (historically known as an “ordinary bicycle”), a retronym, since there was then no other kind. It featured a tubular steel frame on which were mounted wire-spoked wheels with solid rubber tires. These bicycles were difficult to ride due to their very high seat and poor weight distribution.
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