The reason people once thought there was a civilization on Mars was because they could see 'canals' on Mars. With better equipment these canals vanished, but the idea stuck..
Percival Lowell, prime exponent of the Martian canals, thought that there was a *current* civilization on Mars. Today we know that conditions on Mars rendered it conceivably habitable by higher forms of life a very long time ago, but not now. Since Mars is substantially smaller than Earth, it could have cooled from its hot primordial state sooner than Earth did. This might have allowed it to get a head start on Earth life. This just might have progressed to the point of civilization, long before humans appeared on Earth.