In 1930, photographic evidence of Pluto (now designated a "dwarf planet") was discovered by Clyde W. Tombaugh at Lowell Observatory in Flagstaff, Arizona.
Should have left it a planet.
There's a book called "The Pluto Files", by Neil deGrasse Tyson, about the history of Pluto, its status being changed, and the backlash they got for it. Good read.