The twenty-first century began on January 1, 2001. Rules abiding by the Gregorian calendar, which is still used today, the first century began on 1 AD and continued through 100 AD. The twentieth century started in 1901 and ran through the year 2000, with the new century beginning on January 1, 2001. At the turn of the century, we saw the first landing of a spacecraft, NEAR Shoemaker, on an asteroid, 433 Eros, the first blind person, Erik Weinhenmayer, to reach the summit of Mount Everest, and the debut of the first Harry Potter film. Wikipedia also debuted on January 15, 2001.