By next year it should be able to make cables a third of a kilometre long.

ECONOMIST: Superconductors are starting to become useful

Situated in north-eastern Wales, the 18 kilometre long Pontcysyllte Aqueduct and Canal is a feat of civil engineering of the Industrial Revolution, completed in the early years of the 19th century.

UNESCO: World Heritage

Already a sand-bank, a trench and an electrified fence guard the 200-kilometre-long border.

ECONOMIST: Preparing for the worst

Before long, I'm stuck in a traffic jam stretching for more than a kilometre.

BBC: Viewpoint: Bad case of Baghdadophobia

He has long been afraid of a flood of Afghan refugees across the 1, 300-kilometre (800-mile) border that the two countries share.

ECONOMIST: The battle for Afghanistan