The 20th Century was that century which lasted from 1901 through 2000 in accordance with the Julian calendar in the Common Era.
- The church on the Windrow Estate (New York) is built sometime during this decade (The Revenge of the Wizard's Ghost, 81).
- Henry “Cyclone” Dixon was pitching for the Duston Heights Spiders in this decade (The Eyes of the Killer Robot, 8).
- An effort is made in the 1950s to finish the Cathedral of Saint Gorboduc by allowing the pennies of Catholic school children to fund completion of the ancient church (Saint Fidgeta and Other Parodies, 36)
|Events Before the Common Era|
|Centuries in 1st Millennium||1st | 2nd | 3rd | 4th | 5th | 6th | 7th | 8th | 9th | 10th|
|Centuries in 2nd Millennium||11th | 12th | 13th | 14th | 15th | 16th | 17th | 18th | 19th | 20th|
|Centuries in 3rd Millennium||21st | 22nd | 23rd | 24th | 25th | 26th | 27th | 28th | 29th | 30th|