The Limit

Sir Norman Foster and engineer Dr Keizo Shimizu want to build a skyscraper nearly a kilometre tall.

For a decade, David Giles has striven to beat the waves that hinder the passage of cargo ships. Now he may be close to cutting by half the time it takes to cross the Atlantic.

Hugh Doherty has spent a lifetime tunnelling underground, from the Clyde River Tunnel to the Hong Kong Mass Transit System. But now he is facing his biggest challenge yet - to build a new tube line under the heart of London, in record time.

The battle is on to build the world's largest passenger aeroplane and leading the competition is Jean-Jacques Huber, of Airbus Industrie, with his plans to construct a super-Jumbo

The world's longest single bridge span is set to arch for more than a mile over the Baltic Sea, part of an audacious plan to link Germany via Denmark to Sweden.

In this week's programme, the race is on to design the ultimate robot drill. Its seemingly impossible task is to catch up with a comet some 600 million kilometres from Earth and, in zero gravity, drill into its forbidding surface.