In a series of engineering firsts, two interstate highways are being rebuilt beneath Boston, sending its traffic 120 feet underground! The "Big Dig" will take more than 30 years to build, but not without confronting unprecedented challenges.

Build the tallest skyscraper in Northern Europe? Only hope they're up to the challenge. And there's a catch: this twisted nightmare of a structure has to complete a 90-degree turn before reaching its final floor, 600 feet up.

Find out what measures are required of Venetians as experts attempt to keep the world's most beautiful city from going underwater.

In a remote corner of France, traffic between the south of France and Paris and the north have run into huge bottlenecks. Designers and engineers are working to open the region by building a bridge to leap across the 1.3-mile wide gorge.

At the world's largest open pit iron mine, a $10 million custom-built super shovel is commissioned to meet a sudden worldwide surge in the demand for iron. Will miners find success with the fastest, most technologically advanced excavator ever made?

New cargo vessels are changing the industry. Shipbuilders are making them so huge, they require the re-dredging and retrofitting of the world's cargo ports and canals.

The Eastern Highland, a vast plateau 100 miles south of the Arctic Circle, is the site of a bold challenge of extreme engineering. World-class tunnel diggers are carving more than 45 miles of tunnels through solid rock hundreds of feet underground.

Charleston, South Carolina, is the construction site of the longest cable-stay bridge in America. Its signature 500-foot, diamond-shaped towers and ribbon-thin, eight-lane road surface will ensure its place among the world's most stunning structures.

America runs on oil. One-third of that oil gets pumped from wells in the Gulf of Mexico. Follow the dangerous construction of the real workhorses of America's offshore drilling industry- the massive, mobile contraptions known as jack-up rigs.

The New Bay Bridge is the biggest construction project in California history. This two-mile, earthquake-proof road will replace the most heavily trafficked bridge in the country-the span linking San Francisco to Oakland and the East Bay.

Snohvit is Europe's first liquefied natural gas plant being built in the port of Cadiz in Spain. It's the first time a natural gas treatment plant has been built so far away from where it will be installed: the icy Arctic Circle.

The El Cajon Dam on the Rio Grande de Santiago River in Mexico is the largest current construction project in Latin America. A fast building effort, when completed, this $750 million structure will be able to supply 2% of Mexico's electricity needs.

On Hong Kong's Lantau Island a team of experts are building one of the most impressive cable cars ever seen. This year-round system, the Ngong Ping 360, is not only the longest detachable cable car system but the biggest.

The Woodrow Wilson Bridge that has spanned the Potomac River since the 1960s is proving inadequate for the demands of the 21st Century. A replacement is being constructed, featuring seven more miles of roadway to connect Virginia and Maryland.

The Gotthard Base Tunnel will soon be the world's largest rail tunnel, creating a flat rail link for travel through the Alps. With breakthrough engineering methods, this project is undoubtedly one of the most exciting and dramatic of modern times.

Ski-Dubai offers what seems impossible - snow in the desert. Rising from the sea of sand that surrounds Arabia's most vibrant city, it's the first indoor slope with a black ski run and will provide the complete indoor alpine experience.