A roller coaster is an amusement park ride that features a track with steep drops, sharp turns, and loops. Riders sit in cars that are attached to the track and are lifted to a high point before descending rapidly. The thrill comes from the speed and the feeling of weightlessness during the ride. Roller coasters can vary in design, with some being wooden and others made of steel. They are categorized by their layout, such as inverted coasters, where riders hang below the track, or hybrid coasters, which combine both wood and steel elements. Safety measures, like harnesses and brakes, are essential for rider protection.