* The Taiping Rebellion, led by a man named Hong Xiuquan who believed himself the younger brother of Jesus Christ, is thought today to have been the most destructive war of all time: twenty million people are said to have died during its fourteen years. Frederick Townsend Ward, an American, and Charles ‘Chinese' Gordon, a Briton who later died a hero in Khartoum, led the Chinese Ever-Victorious Army in successfully defending Shanghai from the Taiping onslaught.

* It is possible, through judicious use of skeleton keys or a credit card, to open the locked steel door that leads from a staircase in one of the bridge towers, out onto the forbidden railway deck. There can be few more unforgettable sights of raw industrial majesty than this – an endlessly vanishing abyss of iron latticework, the thundering of the trucks speeding overhead, the roaring of the swirling waters streaming by below, and then an express train, its headlights burning brilliantly, rushing towards you at full tilt.

* Unlike most of the treaty ports, Nanjing never had a formal foreign concession area where the victims might have sought sanctuary. The 1858 agreement that added Nanjing to the growing list of ports was not actually taken up until 1899, because of the frightful devastation of the city caused by the Taiping Rebellion. But the land suggested for a concession, which lay outside the city walls and on the banks of the Yangtze, was swampy, malarial and more unpleasant even than the Shanghai waterfront. The foreigners never took the offer up.

* Where he captured a giraffe and brought it back for the Emperor of the day to see. Cheng Ho is still revered as China's equivalent of Columbus, or Magellan; but in fact he was not properly Chinese, being a Muslim from a minority tribe, as well as a eunuch.

* The compensation was paid in silver, sixty-five tons of it arriving on a ship at Portsmouth in 1842 and being taken promptly to the Royal Mint.