For a time in the late 19th and early 20th centuries, it was erroneously believed that there were canals on Mars. These were a network of long straight lines in the equatorial regions from 60° N. to 60° S. Lat. on the planet Mars. They were first described by the Italian astronomer Giovanni Schiaparelli during the opposition of 1877, and confirmed by later observers. Schiaparelli called these canali, which was translated into English as "canals". The Irish astronomer Charles E. Burton made some of the earliest drawings of straight-line features on Mars, although his drawings did not match Schiaparelli's. By the early 20th century, improved astronomical observations revealed the "canals" to be an optical illusion, and modern high resolution mapping of the Martian surface by spacecraft shows no such features.
Mars.
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The Italian astronomer Giovanni Schiaparelli, observing Mars through his telescope, described "canali" on the surface of the planet. While the British press seized eagerly upon the concept of "canals" - obviously artificially dug, by some alien intelligences! - the fact is that the Italian word "canali" means "channels", not "canals". Schiaparelli never intended that people should interpret his "canali" as anything other than natural features.
Early astronomers used to think that the planet Mars has canals on the surface. Their telescopes at the time were not good enough to show better detail.
the answer is mars because people thought they saw canals on it but their telescopes were not that good to show good detail
Earth is the only one we know of.
Its longest canal is the Grand Canal in China, about 1776 km long, and was completed about 600 CE.
Mars. See related link for more info.
mars
Earth
Mars.
It has never been a planet, some people might of thought it was a planet, but it has never officially been one.
Jupiter
venus
Mars
Mars as of the large lines that were thought to have water in them.
Mars. The Italian astronomer Schiaperelli thought he could see "canali" (channels, not actually canals) on the planet's surface. Percival Lowell also "saw" them, and wrote an extensive book on what Mars was probably like because of the "canals". It was determined years later, and proven by the Mars orbiters and landers, that the "canals" were an optical illusion to earth-bound viewers. They don't exist.
He was called Giovanni Schiaparelli , he thought he saw canals on Mars.
The Polar ice caps , its red colour and the dark lines that were once thought to be canals. see realted link for picture
Neptune is a gas planet, thus it has no solid surface (that we've seen yet), thus no canals.
well other then earth its mars
Pluto was thought to be a planet until 2006, when it was named as a dwarf planet. The planet is thought to be very icy and at least 5 times smaller than Earth.
That would be Pluto -- and it is not a planet, it is indeed a comet.
Because canal barges were drawn by horses before engines were ever thought of....
No planet except earth has canals. There was at one time an idea the Mars had "canals" which might indicate a civilization there. However this was due to a combination of mistranslation and mistaken observations. The mistranslation happened when a paper by an Italian astronomer on his observations of Mars was translated to English: the italian word "canali" (meaning channels, gullies, or canals) was translated as "canals" with the implication that they were artificial when all the Italian astronomer had meant was he had seen straight lines on Mars. The mistaken observations were eventually traced to an optical illusion where the human visual system has a strong tendency to find patterns in "random images" that are not actually there.
Mars