How Did They Build That? - Season 4

Lives are on the line creating the International Space Station, a scientific marvel a decade in the making, that changes the way we look at the world.

A floating museum honors military heroes in Texas. A sky-park casino balances on six towers. And an office is carved out to protect NYC's High Line.

A railway-spanning library mimics the clouds. A speed-core skyscraper is built in record time. And a world first bridge inspired by a child's toy.

Apartments hanging 164 feet above the water defy gravity in Amsterdam. A trio of towers shimmer on Chicago's skyline, and museum design is revolutionized in Paris.

An airport gets a 9 acre roof without stopping flights. A museum is buried in the desert to keep it cool. And building San Fran's most hated tower.

A 284ft timber tower tests fire safety limits. An old crane tracks is reborn as sleek glass offices. And 28 apartments are stacked on a 21ft plot.

A mountain-top centre defies extreme altitude. A stunning museum is sunk into an old dock. And a 600ft tower with floating gardens rises in Singapore.

A museum bends 1,100 glass tubes into a bold facade. A vast atrium rises where the Berlin Wall fell, and a NJ bridge is raised 65ft for huge tankers.

A 70,000 seat stadium defies seismic forces in LA. Malta's 33 story tower twists around old vaults. And an 807ft elevator test tower spirals skywards.

San Francisco's MOMA dramatically triples in size. A skyscraper transforms by smart demolition. And 5 acres of parkland floats above Dallas traffic.