Speculation that we are not alone in the Universe goes back to ancient times with the Greek philosopher Epicurus (341-270 BCE) arguing that there were infinitely many worlds some of which would be like our own. Even in more recent times, there was the 1877 discovery of canali (channels) on Mars by the Italian astronomer Giovanni Schiaparelli, a word that was mis-interpreted as canals implying artificial structures. This led to considerable speculation that there was intelligent life on the red planet, an idea especially popularized by the American astronomer Percival Lowell in several books even into the twentieth century.