Unearth the technological leaps forward that have allowed the world's longest tunnel - the Gotthard Base Tunnel - to be built. The Gotthard Base Tunnel stretches 57 kilometres through the heart of the Swiss Alps. It is deeper than any other tunnel on Earth and paves the way for a vital high-speed rail link between Zurich and Milan. 2000 workers and four gigantic tunnel boring machines work flat-out to excavate 24 million tonnes of mountain rock to complete the tunnel. Explore how this structure was made possible through a series of six engineering breakthroughs. See how six landmark tunnels - including the Thames Tunnel and Channel Tunnel - each feature an ingenious technological innovation that have enabled tunnels to grow ever longer.

Uncover the technological leaps forward that allowed the world's largest Oil Platform - the Perdido Spar in the Gulf of Mexico - to be built. The Perdido Spar sits in deeper water than any other oil platform, in an ocean over two kilometres deep. This floating factory is capable of drilling in any direction, and in depths of up to three kilometres below the sea floor. At maximum production it can generate enough oil daily to fill 132,000 cars with petrol. Count down the six technological leaps in landmark oil platforms like the Beryl Alpha platform, that enabled this, the world's largest oil platform, to be built and survive in ever deeper waters.

Filter through the technological leaps forward that have allowed the world's largest hydroelectric dam - the Three Gorges Dam in China - to be built. The Dam harnesses the power of China's great Yangtze River. It is over two kilometres long, towers over 60 storeys high and creates a reservoir 600 kilometres in length. On completion the scheme will be able to generate 22,500 megawatts of power - enough to supply electricity to 60 million people. At its peak, over 25,000 men and women were working round the clock to make what was once Chairman Mao's dream a reality. Explore how this immense project was made possible through a series of breakthroughs on six landmark dams - including the Hoover Dam in America. Each features a major technological innovation that allowed engineers to create bigger dams to generate ever more hydroelectric power.