The late nineteenth century was all about canal building. The Suez Canal (pictured here) was completed in 1869, and reduced the travel distance between the North Atlantic and northern Indian Oceans by 4,300 miles by creating a shortcut from the Mediterranean to the Red Sea, through Egypt. The Panama Canal went online a mere eleven years later.
Telescopes were getting bigger and better at this time as well, and astronomers were spending long hours staring at neighboring planets (astrophotography wasn’t a thing yet) and mapping any discernible surface features their optics would resolve. In 1877 Italian astronomer Giovanni Schiaparelli observed a number of what he believed to be naturally occuring “canali”, an Italian word meaning “channels”, on the Martian surface. The word’s similarity to the English word “canal”, which refers specifically to an artificial waterway, led to years of bad astronomy in the person of well-to-do American astronomer Percival Lowell. Lowell devoted much of his later career to advancing his theory that the canals had been constructed by intelligent beings in order to redirect badly-needed water from the Martian poles to population centers nearer the planet’s equator.
Although most of Lowell’s contemporaries dismissed his ideas, it wasn’t until the Mars Mariner missions in the 1960s that remote sensing data could definitively prove him wrong.