On December 27th, 537, the Hagia Sophia was completed.

On December 26th, 1898, Marie and Pierre Curie announced the isolation of radium.

On December 25th, 2003, the Beagle 2 disappeared shortly before its landing.

On December 24th, 1914, the World War I "Christmas truce" began.

On December 23rd, 1986, the Voyager became the first aircraft to fly non-stop around the first.

On December 22nd, 1989, the Brandenburg Gate reopened, effectively ending the division of East and West Germany.

On December 21st, 1872, the HMS Challenger set sail from Norfolk, commanded by Captain George Nares.

On December 20th, 1951, nuclear power was first harvested when EBR-1 lit four light bulbs.

On December 19th, 1972, Apollo 17 returned to Earth.

On December 18th, 1966, Saturn's moon Epimetheus was discovered.

On December 17th, 1903, the Wright Brothers made their first powered Heavier-than-Air flight in the Wright Flyer at Kitty Hawk.

On December 16th, 1773, the Boston Tea Party took place.

On December 15th, 1965, the Gemini 6A was launched from Florida.

On December 14th, 1896, the Glasgow Underground Railway was opened.

On December 13th, 1545, the Council of Trent began.

On December 12th, 1781, the HMS Victory defeated the French fleet during the Revolutionary War.

On December 11th, 1872, P.B.S. Pinchback was sworn in as the first African-American member of the U.S. House of Representatives.

On December 10th, 1901, the first Nobel Prizes were awarded.

On December 9th, 1851, the first YMCA in North America was established in Montreal.

On December 8th, 1609, Biblioteca Ambrosiana, the second public library in Europe, opened.