He believed they indicated the existence of an advanced civilization on Mars and wrote several books on the subject in the early 20th century. He proposed that the canals carried water from the wet polar regions to the dry equatorial deserts. As telescopes improved, however, astronomers found it more and more difficult to see Lowell's canals. Images of Mars's surface from the Mariner spacecraft finally proved that the canals did not exist. Lowell's beliefs about civilization on Mars have had a powerful effect on human perception of the planet.
Some people believe in the existence of a civilization on Mars even today.
The so-called Face on Mars is thought by some people to be evidence of intelligent life on Mars. This feature, shown in Viking images of the Cydonia region of Mars, looks vaguely like a humanoid face. Geologists' views of these features are quite different. The Cydonia region lies near the boundary of the southern highlands and the northern plains and contains a large number of isolated hills, the eroded remnants of the edge of the highland terrain. These hills resemble the mesas of the U.S. Southwest.