1258
The taking of Baghdad by Hülegü, from a Mughal copy of Rashid al-Din’s history made in northern India in 1596 (Cincinnati Art Museum).Image: Sailko · CC BY 3.0world · Asia
The Mongols take Baghdad and end the Abbasid caliphate
For five centuries Baghdad had been the seat of the Abbasid caliphs, the heads of the Sunni Muslim world, and one of the great cities of learning. By the 1250s the caliphs’ real power was small, but their prestige was immense. The Mongol ruler Möngke sent his brother Hülegü west to bring the Islamic lands to heel. Hülegü’s army surrounded Baghdad in January 1258, and after its walls were breached the caliph al-Mustasim surrendered. The city fell on 10 February 1258. The Mongols sacked it, killing a great part of its population, and the caliph was put to death soon afterwards. For the first time in its history, Islam was left without a caliph in Baghdad.
Source: Encyclopaedia Britannica: Iraq, the later Abbasids (1152-1258) ↗
Carfax Tower in Oxford, photographed in 1968. The Swindlestock tavern, where the riot began, stood at the Carfax crossroads.Image: 
A new map of North America published in London in 1763, showing the colonies of the European powers ‘according to the definitive treaty concluded at Paris’.Image: 
The Marriage of Queen Victoria, 10 February 1840, painted by Sir George Hayter (Royal Collection).Image: 
The Glienicke Bridge between Potsdam and Berlin, where the exchange took place, seen from the Potsdam bank in 2018.Image: 
An IBM computer of the Deep Blue type, on show at the Computer History Museum in California.Image: