In times before space exploration was possible, Mars was often thought as another planet capable of supporting life. Scientists such as Lowell claimed to see an intricately designed and built canal system that crisscrossed the surface, leading to only one logical conclusion: intelligent life exists on Mars.
In addition to this observation, scientists also observed what seemed to be seasonal color changes on the surface of the planet, possibly the evidence of a seasonal cycle accompanied by new born vegetation comparable to that on Earth.
In great anxiety, NASA launched the Mariner 4 in the July of 1965 to photograph the surface of Mars. 22 pictures were transmitted back to Earth only to reveal great barren canyons, large craters and lots of apparently inactive volcanoes. There was no sign of life or water anywhere. However, scientists did not give up hope and in July and September of 1976, two exploratory vehicles, Viking Landers 1 & 2 landed on the surface of Mars.
War of the Worlds
In 1938, Orson Welles broadcased a radio program entitled the War of the Worlds. Intended only for entertainment, the broadcast was so realistic, thousands of people listening to the radio at that time ran out of their houses terrified.
This incident repeated itself again a short time later, and this time the radio station broadcasting the program was destroyed by furious citizens.
They performed a series of biological experiments intent on searching for any evidence of living microorganisms. Instead, the Landers found chemicals that may suggest a hint of life in the soil, but clearly does not prove it. After further analysis, scientist concluded that Mars is incapable of supporting life due to the constant bombardment of ultra-violet radiation and harsh conditions of the climate.
The search continued twenty years later with the landing of the Mars Pathfinder mission which, in addition to performing chemical analysis on the soil, still did not reveal any evidence of life. Thus the search continues...