Martian canal

A 1962 map of Mars published by the U.S. Aeronautical Chart and Information Center, showing canals snaking through the Martian landscape. At the time, the existence of the canals was still highly controversial as no close-up pictures of Mars had been taken (until Mariner 4's flyby in 1965). During the late 19th and early 20th centuries, it was erroneously believed that there were "canals" on the planet Mars. These were a network of long straight lines in the equatorial regions from 60° north to 60° south latitude on Mars, observed by astronomers using early telescopes without photography.

They were first described by the Italian astronomer Giovanni Schiaparelli during the opposition of 1877, and attested to by later observers. Schiaparelli called these canali ("channels"), which was mistranslated into English as "canals". The Irish astronomer Charles E. Burton made some of the earliest drawings of straight-line features on Mars, although his drawings did not match Schiaparelli's.