Ferris wheel

A Ferris wheel (also known as an observation wheel or big wheel) is a nonbuilding structure consisting of a rotating upright wheel with passenger cars (sometimes referred to as gondolas or capsules) attached to the rim in such a way that as the wheel turns, the cars are kept upright, usually by gravity. Some of the largest and most modern Ferris wheels have cars mounted on the outside of the rim, and electric motors to independently rotate each car to keep it upright.