Great and greater walls

Mao Zedong famously proclaimed: "He who has not climbed the Great Wall is not a real man!" He neglected to follow up with: "but one who has saved his hamstrings from a real soreness!"

While there's a general consensus the bulwark lives up to the "great" part of its namesake, referring to the "wall" in singular form is something of a misnomer. It's actually a network of separate fortifications built between the 6th century BC and the 16th century, snaking 6,400 km from Shanhaiguan in Hebei province to Luobupo in the Xinjiang Uygur autonomous region.

In Beijing, 629 km of the garrison threads through the city's northern suburbs. A relatively small section, 30 km, is open to tourists.