Impossible Engineering (UK)

Constructing the Gotthard Base Tunnel in Switzerland, the longest rail tunnel in the world, running for 57 kilometres through the Alps.

The spacecraft designed for the first manned mission to Mars, planned to launch by 2035, which requires the most powerful rocket ever built and a specially designed crew module.

The Three Gorges Dam, built across China's Yangtze river, which is the largest and heaviest concrete structure ever built, housing the world's largest power station.

The Millau Viaduct in South West France, which is the tallest bridge in the world and stretches two and a half kilometres over one of Europe's deepest valleys.

A colossal American football stadium in Texas, that features the world's largest retractable roof and is able to seat over 100,000 spectators with no restricted viewpoints.

Examining a fleet of cruise ships that are the largest passenger vessels in the world, and revealing how they have built on 19th-century experiments in hydrodynamics.

The construction of London's Shard, revealing how it was influenced by the Milan Metro, concrete grain storage in Minnesota and a lifting mechanism in the Venice shipyards.

A look at the US navy's most advanced nuclear submarine - which can remain underwater for months at a time - examining the previous vessels that influenced it.