Percival Lowell
Lowell crater is named for Percival Lowell who built the Lowell Observatory in Flagstaff, Arizona, in 1894, and then started observing Mars intensively for years. He used the observatory and his large refractor telescope to discover what he believed were over 500 canals on Mars. Lowell promoted the idea that they were constructed by an intelligent race of Martians. However, when pictures were received from spacecraft, the canals were found to be optical illusions.