Just over a century ago, it was customary to see signs of an alien civilisation on the red planet. Italian astronomer Giovanni Schiaparelli (1835–1910) thought he saw canals on Mars.
Many others, including Percival Lowell (1855–1916), adopted this view.
This hasn’t extinguished speculations. Recently, US congressman Dana Rohrabacher asked during a hearing of the U.S. House of Representatives' Committee on Science, Space and Technology's Space Subcommittee whether Mars was home to an alien civilisation just a few thousand years ago.