Season 6

1. Tunnel Vision

Return to the 57-kilometer long high-speed rail tunnel in Switzerland's Gotthard Mountain range to see what it will take to finish the project by 2017.

2012-03-15 • 46 min

2. Extreme Surf Machine

Returning to Tenerife to check on the world's best water park which now seems destined to remain dry after numerous problems.

2012-03-22 • 46 min

3. Race to the Games

Crews race against the clock to finish an important venue and signature landmark for the 2012 London Olympics.

2012-03-29 • 46 min

4. Tunneling Through History

Mega Builders return to Istanbul to update the Marmaray rapid-transit project, which continues to have delays.

2012-02-05 • 46 min

5. Quake-Proof Bridge

Six years after piles were pounded into the muddy bottom of San Francisco Bay the new Bay Bridge is about to be topped off.

2012-02-12 • 46 min

6. Ice Hotel Bigger Colder

Inside a famous Swedish hotel which is constructed from 10,000 tonnes of ice and 30,000 tonnes of snow, and boasts a frozen bar and cinema screen.

2012-02-19 • 46 min