First "evidence" of intelligent life on Mars

In 1877 the Italian astronomer Giovanni Schiaparelli described his telescopic observations of Mars to include "canali", or channels – a network of straight lines across the surface, which did not look natural. "Canali" was interpreted by some as "canals", and later observers including Percival Lowell (USA) mapped them in detail, believing them to be structures built by an intelligent Martian civilization. As telescopes became more powerful during the 20th century, it became apparent that the Martian canals were nothing more than optical illusions. Space probes sent to Mars showed no evidence of them.