January 27

Trajan succeeds his adoptive father Nerva as Roman emperor, ushering in a period of significant imperial expansion.

Trajan, a respected military commander adopted as heir by the childless and increasingly unpopular Emperor Nerva, succeeded him peacefully upon his death. Trajan went on to expand the Roman Empire to its greatest territorial extent, conquering Dacia and parts of Mesopotamia, and is remembered as one of the "Five Good Emperors" who presided over a golden age of stability.

Poet Dante Alighieri is condemned and exiled from Florence.

Dante's exile from his native Florence, imposed by a rival political faction after he backed the losing side in a bitter power struggle, was ostensibly for corruption but was widely understood as political persecution. He never returned to the city and spent the rest of his life writing, including his masterpiece "The Divine Comedy," partly as a reflection on the political turmoil that had exiled him.

The trial of Guy Fawkes and other Gunpowder Plot conspirators begins in London.

Guy Fawkes and his fellow conspirators stood trial for the failed 1605 plot to blow up the Houses of Parliament and assassinate King James I using barrels of gunpowder hidden in a cellar beneath the building. Convicted of treason, most of the plotters, including Fawkes, were executed. The foiled plot is still commemorated annually in Britain on Guy Fawkes Night.

A Russian naval expedition led by Bellingshausen and Lazarev sights the Antarctic continent for the first time.

The Russian expedition, led by Fabian von Bellingshausen and Mikhail Lazarev, sighted an ice shelf now believed to be the first documented sighting of the Antarctic continent, though the claim has long been disputed by rival British and American expeditions that also claimed early sightings around the same time. Antarctica remained largely unexplored for another century afterward.

Forces loyal to the Japanese emperor defeat the shogunate at the Battle of Toba–Fushimi, a turning point in the Meiji Restoration.

Forces loyal to the young Emperor Meiji defeated troops of the Tokugawa shogunate near Kyoto, a pivotal early battle of the Boshin War that decided the future direction of Japan. The shogunate's defeat cleared the path for the sweeping Meiji Restoration reforms that would rapidly modernize and industrialize Japan over the following decades.

The 872-day Siege of Leningrad is lifted by Soviet forces during World War II.

The siege, one of the longest and deadliest in modern history, had trapped Leningrad's population under German blockade for nearly two and a half years, causing mass starvation that killed an estimated one million civilians. Its lifting by Soviet forces was celebrated with a 24-gun salute in the city, and it remains a defining, deeply commemorated event in Russian historical memory.

Soviet troops liberate the remaining prisoners at the Auschwitz-Birkenau concentration camp.

Soviet troops entering Auschwitz-Birkenau found roughly 7,000 surviving prisoners too weak to have been forced on the earlier death marches, along with evidence of the camp's machinery of mass murder. The date is now observed internationally as Holocaust Remembrance Day, commemorating the roughly six million Jews and millions of others killed during the Holocaust.

A cabin fire during a launch pad test kills all three Apollo 1 astronauts; the same day, the Outer Space Treaty is signed by major spacefaring nations.

A flash fire swept through the Apollo 1 command module during a routine ground test, killing astronauts Gus Grissom, Ed White, and Roger Chaffee before they could escape the sealed capsule. The tragedy, attributed to faulty wiring and a pure-oxygen cabin atmosphere, led to a major redesign of the spacecraft and delayed the Apollo program by over a year, though it ultimately made later missions safer.

The Paris Peace Accords are signed, officially ending direct U.S. involvement in the Vietnam War.

The accords, negotiated primarily between U.S. National Security Advisor Henry Kissinger and North Vietnamese official Lê Đức Thọ, established a ceasefire and the withdrawal of remaining U.S. troops from Vietnam. Fighting between North and South Vietnam continued afterward, however, and the South Vietnamese government ultimately collapsed when North Vietnamese forces captured Saigon in 1975.

Apple unveils the iPad, launching the modern tablet computer market.

Steve Jobs introduced the iPad as a new category of device positioned between a smartphone and a laptop, drawing some initial skepticism about whether consumers actually needed another gadget. It went on to sell millions of units within its first year and helped popularize the modern tablet computer, reshaping how people consume media and use apps on the go.