Percival Lowell
13 March 1855 — 12 November 1916
Percival Lowell was an American businessman, author, mathematician, and astronomer who fueled speculation that there were canals on Mars, and furthered theories of a ninth planet within the Solar System. He founded the Lowell Observatory in Flagstaff, Arizona, and formed the beginning of the effort that led to the discovery of Pluto 14 years after his death.
A memorial on Digital Cemetery, an endless map you can explore. This grave stands at coordinates -45, 42.