1910
- Boy Scouts Established in U.S.
- Halley's Comet Makes an Appearance
- The Tango Catches On
1911
- The Chinese Revolution
- Ernest Rutherford Discovers the Structure of an Atom
- The Incan City of Machu Picchu Discovered
- Mona Lisa Is Stolen
- Roald Amundsen Reaches the South Pole
- Standard Oil Company Broken Up
- Triangle Shirtwaist Factory Catches on Fire
1912
- Oreo Cookies First Introduced
- Parachutes Invented
- Piltdown Man, the "Missing Link," Discovered (Fraud)
- The Titanic Sinks
1913
- First Crossword Puzzle
- Henry Ford Creates Assembly Line
- Los Angeles Owens Valley Aquaduct Opened
- Personal Income Tax Introduced in U.S.
1914
- Archduke Ferdinand Assassinated
- Battle of the Marne
- Charlie Chaplin First Appeared as the Little Tramp
- First Traffic Light
- Panama Canal Officially Opened
- World War I Begins
1915
- Armenian Genocide
- D.W. Griffith's The Birth of a Nation Released
- Germans Use Poison Gas as a Weapon
- Lusitania Sunk by German U-Boat
- Second Battle of Ypres
1916
- Battle of the Somme
- Battle of Verdun
- Easter Rising in Ireland
- First Self-Service Grocery Store Opens in U.S.
1917
- First Pulitzer Prizes Awarded
- Mata Hari Executed for Being a Spy
- Russian Revolution
- U.S. Enters World War I
1918
- 1918 Spanish Flu Pandemic
- Daylight Saving Time Introduced
- Russian Czar Nicholas II and His Family are Killed
