September 11

Germanic tribes annihilate three Roman legions at the Battle of the Teutoburg Forest, halting Roman expansion east of the Rhine.

An alliance of Germanic tribes led by Arminius ambushed and annihilated three entire Roman legions marching through dense forest terrain in what is now northwestern Germany, one of the most catastrophic defeats in Roman military history. The disaster convinced Rome to abandon further expansion east of the Rhine River, establishing a lasting frontier boundary.

Scottish forces under William Wallace defeat English troops at the Battle of Stirling Bridge.

Scottish rebel forces under William Wallace achieved a stunning victory over a much larger English army by exploiting the narrow crossing point of Stirling Bridge, funneling English troops into a bottleneck where they could be overwhelmed. The victory made Wallace a celebrated Scottish national hero and temporarily secured Scottish independence.

Ottoman forces withdraw from Malta, concluding the Great Siege of Malta.

After an exceptionally brutal four-month siege that decimated both the defending Knights Hospitaller and the attacking Ottoman forces, the Ottomans finally abandoned their campaign to capture the strategically vital island of Malta. The successful defense is often credited with halting further Ottoman expansion into the western Mediterranean.

A coalition led by Polish King John III Sobieski lifts the Ottoman siege of Vienna.

A coalition of Polish, Austrian, and German forces led by Polish King John III Sobieski launched a decisive relief attack that broke a two-month Ottoman siege of Vienna, a battle widely regarded as a turning point that halted Ottoman expansion into Central Europe.

A peace conference on Staten Island between British and American representatives fails to prevent continued war.

Representatives of the Continental Congress met with British General William Howe on Staten Island in a last diplomatic attempt to resolve the growing conflict, but the talks collapsed over Britain's refusal to recognize American independence as a starting condition for negotiation.

American forces achieve a decisive victory at the Battle of Plattsburgh during the War of 1812.

American naval and land forces achieved a decisive combined victory over invading British troops at Plattsburgh, New York, forcing a British retreat back into Canada and significantly strengthening the American negotiating position in the peace talks that soon concluded the War of 1812.

Construction begins on the Pentagon building outside Washington, D.C.

Construction began on what would become the world's largest office building by floor area, designed to consolidate the rapidly expanding U.S. War Department's scattered offices into a single, efficient headquarters ahead of America's anticipated entry into World War II. The massive five-sided structure, built in just sixteen months on a tight wartime schedule, remains the headquarters of the U.S. Department of Defense today.

A military coup led by General Augusto Pinochet overthrows Chilean President Salvador Allende.

Backed covertly by the United States amid Cold War anti-communist policy, General Pinochet led a military coup that overthrew Chile's democratically elected socialist president, Salvador Allende, who died during the assault on the presidential palace. Pinochet subsequently ruled Chile as a military dictator for the next seventeen years.

Hungary announces that East German refugees are free to cross into West Germany, an early crack in the Iron Curtain.

As part of a symbolic "Pan-European Picnic" event, Hungarian authorities opened the border with Austria, allowing thousands of East German citizens vacationing in Hungary to cross into the West, an early and significant breach in the Iron Curtain that helped accelerate the collapse of East Germany's government.

Terrorists hijack four commercial aircraft in coordinated attacks that kill nearly 3,000 people in New York, Washington, and Pennsylvania.

Nineteen terrorists affiliated with al-Qaeda hijacked four commercial passenger jets, crashing two into the World Trade Center towers in New York, one into the Pentagon, and a fourth into a field in Pennsylvania after passengers fought back, killing nearly 3,000 people in the deadliest terrorist attack in world history.