The kilometer (from the Greek word for “thousand”) is a unit of length, equal to 1000 meters. It was first proposed in 1875 by the French scientist Georges Le Verneur, and was first used in 1880. The SI base unit of measurement is the meter, but since 2006, the kilometer has been recognized as an official unit of measure by the General Conference on Weights and Measures (CGPM), alongside the meter, kilogram and second. The kilometer is not officially defined, but it is based on the distance that light travels in a vacuum in 1/299.792 of a second.

The foot is the basic unit of length in the metric system and is equal to 3.2808 meters. It’s also the primary unit of linear measure in customary systems of measurement, including the English system. The foot is defined as the length of a line from the heel of one person to the toe of another person, with each foot positioned at the same level. Originally, a foot was defined as being equal to 12 inches, but this definition was later changed to its current value.