| 145681 | December 26 | Holiday and observance | Independence and Unity Day (Slovenia) |
| 145682 | December 26 | Holiday and observance | Mauro Hamza Day (Houston, Texas) |
| 145683 | December 26 | Holiday and observance | Mummer's Day (Padstow, Cornwall) |
| 145684 | December 26 | Holiday and observance | St. Stephen's Day (public holiday in Alsace, Austria, Catalonia, Croatia, the Czech Republic, Germany, Hong Kong, Italy, Ireland, Luxembourg, Poland, Slovakia and Switzerland), and its related observances:Father's Day (Bulgaria) |
| 145685 | December 26 | Holiday and observance | The first day of Kwanzaa, celebrated until January 1 (United States) |
| 145686 | December 26 | Holiday and observance | The first day of Junkanoo street parade, the second day is on the New Year's Day (The Bahamas) |
| 145687 | December 26 | Holiday and observance | The first of Twelve Holy Days (Esoteric Christianity) |
| 145688 | December 26 | Holiday and observance | The second day of the Twelve Days of Christmas (Western Christianity) |
| 145689 | December 26 | Holiday and observance | Wren Day (Ireland and the Isle of Man) |
| 145690 | December 27 | Event | 537 – The Hagia Sophia is completed. |
| 145691 | December 27 | Event | 1512 – The Spanish Crown issues the Laws of Burgos, governing the conduct of settlers with regard to native Indians in the New World. |
| 145692 | December 27 | Event | 1655 – Second Northern War/the Deluge: Monks at the Jasna Góra Monastery in Częstochowa are successful in fending off a month-long siege. |
| 145693 | December 27 | Event | 1657 – The Flushing Remonstrance is signed. |
| 145694 | December 27 | Event | 1703 – Portugal and England sign the Methuen Treaty which gives preference to Portuguese imported wines into England. |
| 145695 | December 27 | Event | 1814 – War of 1812: The American schooner USS Carolina is destroyed. It was the last of Commodore Daniel Patterson's makeshift fleet that fought a series of delaying actions that contributed to Andrew Jackson's victory at the Battle of New Orleans. |
| 145696 | December 27 | Event | 1831 – Charles Darwin embarks on his journey aboard the HMS Beagle, during which he will begin to formulate the theory of evolution. |
| 145697 | December 27 | Event | 1836 – The worst ever avalanche in England occurs at Lewes, Sussex, killing eight people. |
| 145698 | December 27 | Event | 1845 – Ether anesthetic is used for childbirth for the first time by Dr. Crawford Long in Jefferson, Georgia. |
| 145699 | December 27 | Event | 1845 – Journalist John L. O'Sullivan, writing in his newspaper the New York Morning News, argues that the United States had the right to claim the entire Oregon Country "by the right of our manifest destiny". |
| 145700 | December 27 | Event | 1911 – "Jana Gana Mana", the national anthem of India, is first sung in the Calcutta Session of the Indian National Congress. |
| 145701 | December 27 | Event | 1918 – The Great Poland Uprising against the Germans begins. |
| 145702 | December 27 | Event | 1922 – Japanese aircraft carrier Hōshō becomes the first purpose built aircraft carrier to be commissioned in the world. |
| 145703 | December 27 | Event | 1923 – Daisuke Namba, a Japanese student, tries to assassinate the Prince Regent Hirohito. |
| 145704 | December 27 | Event | 1927 – Show Boat, considered to be the first true American musical play, opens at the Ziegfeld Theatre on Broadway. |
| 145705 | December 27 | Event | 1929 – Soviet General Secretary Joseph Stalin orders the "liquidation of the kulaks as a class", ostensibly as an effort to spread socialism to the countryside. |
| 145706 | December 27 | Event | 1932 – Radio City Music Hall, "Showplace of the Nation", opens in New York City. |
| 145707 | December 27 | Event | 1939 – Erzincan, Turkey, is hit by an earthquake, killing 30,000. |
| 145708 | December 27 | Event | 1939 – Winter War: Finland holds off a Soviet attack in the Battle of Kelja. |
| 145709 | December 27 | Event | 1942 – The Union of Pioneers of Yugoslavia is founded. |
| 145710 | December 27 | Event | 1945 – The World Bank and International Monetary Fund are created with the signing of an agreement by 29 nations. |