HOW LONG DID IT TAKE TO BUILD THE GREAT WALL OF CHINA?

The Great Wall isn’t a single wall at all, but a series of bulwarks and fortifications. The first went up some four centuries before Qin Shi Huang, who became China’s first emperor in 221 BC, ordered a decadelong project to unite and expand these defences into a single barrier.

Construction to create the current 13,000 miles of wall continued, on and off, for more than two millennia. Much of what remains was built during the Ming Dynasty. While intended to keep out foreign invaders, Genghis Khan demonstrated how even a wall as great as this had a flaw. He marched his Mongol horde around one of the sides.

AT GREAT COST At least 400,000 people, many of them slaves, died during the construction of the Great Wall of China

DID YOU KNOW?

A STICKY FOUNDATION

Sections of the Great Wall owe their longevity to a rather unusual mortar – glutinous rice flour. Just as strong and waterproof as cement, this ‘sticky rice’ sealed the bricks so tightly that weeds are unable to grow between them.

ALAMY X1, GETTY X1

TIME FOR TEA Painting one’s legs was all well and good, unless it rained. Then the stain washed o

What did women use for tights in World War II?

Rationing hit wartime Britain hard, on the dinner table and the wardrobe. Women had to sacrifice their nylon stockings, which had only been introduced in 1939, as the material could be put to better use making parachutes, cords and rope.

Yet the propaganda machine kept making it clear that women should not let their standards of dress drop, for fear of the effect on morale.

“Beauty as duty,” read the posters. While stockings could be acquired on the black market, or by getting friendly with an American GI carrying goodies from across the pond, most used a homemade option – adding flavour to their style, though it wouldn’t be everybody’s cup of tea.