Overview
martian canals
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Supposed dark, straight lines on the surface of Mars seen through telescopes from Earth. They were first seen by G. V. Schiaparelli in 1877, and were reported by others until the 1960s when close-up pictures of Mars from the Mariner probes demonstrated them to be illusions. Early in the 20th century, P. Lowell and others considered the canals to be evidence for an advanced Martian civilization.