Series profiling the biggest construction projects. A global project, the International Space Station will cost billions and take years to construct.
A 1200km pipe to pump gas from Norway to the UK is being constructed on the sea bed. But building a kilometre beneath the ocean is problematic.
How are engineers and astronauts from 16 countries building a research centre for this $60bn space station, which orbits earth every 92 minutes?
Will the rollercoaster with the steepest drop on earth, or the longest track in history, or the most crossovers on record, win the battle to be the best?
The UK's main line is being replaced piece by piece like a giant jigsaw. But with 20 million passengers a week it can only be worked on at weekends.
Billions of dollars of diamonds are buried in a barren part of Canada. Finding them first is the difference between going bust and winning big, and the race is on.
It's the biggest subway expansion in history, but will engineers manage to tunnel under this bustling metropolis without collapsing the city's skyscrapers?