Watch Build It Bigger Season 4 in Australia

Danny Forster takes us to Singapore, where the tiny island nation is doing something that's never been done before — building the first ever Skypark. A modern version of the hanging gardens of Babylon, this 7000-ton urban oasis will hang 650 feet in the air on top of 3 soaring skyscrapers.

Rio de Janeiro was recently awarded the two biggest sporting events in the world — the Olympics and World Cup. But before they'll be ready, they still have one major problem — frequent widespread blackouts. So now, Brazil is currently building one of the largest hydroelectric projects in the world. Host Danny Forster takes us into the wilderness 100 miles from Rio, where workers are rapidly building 5 massive canals, and tunneling through 7 mountains, to move a powerful river through two dams — all to make sure that while the whole world is watching Rio, the lights stay on.

Five years after hurricane Katrina, New Orleans is reinventing hurricane protection, with the largest public works project in U.S. history. The centerpiece of the project — a massive 2-mile long, 26-foot high storm surge barrier — is designed to defend against the fiercest storms on earth. Brad Pitt's Make it Right foundation is also pitching in to help rebuild, constructing 150 of the most hurricane resistant homes in the world, in New Orleans' most devastated neighborhood. But with hurricane season looming, engineers have just 18 months to protect the Big Easy before the next hurricane hits.

Kuwait is building the world's tallest twisting structure, the Al Hamra tower. Clad in over 2000 tons of limestone, and capped by a 17-story open restaurant with views of the Persian Gulf, this incredible building is the perfect desert skyscraper.

Travel to the deepest place on Earth, Johannesburg, South Africa's Mponeng Gold Mine. South Africa's economy depends on gold, but recently, productivity has plummeted. Now, Mponeng is fighting back by digging deeper than man has ever gone, towards an untapped gold reef worth $10 billion. Setting a new depth record every day, workers blast through super-heated rock nearly 3 miles down, in the most remote and dangerous construction site on the planet.

The Victorian government has invested nearly $270 million to create one of the most innovative stadiums ever built — the Melbourne Rectangular Stadium. Melbourne wanted their new stadium to be the crown jewel of their sports district — an icon for the entire city — so they've commissioned the most structurally innovative arena in the southern hemisphere. The stadium will be a living, breathing work of art on the outside, and the ultimate athlete and spectator experience on the inside.

The overhaul of the Bay Bridge is one of the biggest construction projects in the country right now. After almost a decade, California is nearing the crucial end of what has become its most expensive public works project ever, the $6 billion dollar rebuilding and earthquake-proofing of the Bay Bridge. This massive overhaul involves building an entirely new approach into San Francisco, retrofitting the 4.5-mile double suspension bridge with more than 17 million pounds of structural steel and completely replacing the 2.2-mile cantilever bridge with a self-anchored suspension bridge, a skyway, and new touchdown into Oakland.

Welcome to the world's longest worksite —thirty- five miles long. Right now, Switzerland's government is spending $18 billion to revolutionize European transit, using the world's largest Tunnel Boring Machine to build the longest tunnel in history — the Gotthard Base Tunnel. Connecting from Southern Germany to Northern Italy, the GBT will circumvent the winding mountain passes that serve as the current transit system, getting people and goods across the Alps up to 3 times faster, and safer than ever before.

Abu Dhabi City is building, and building BIG. They're hard at work on an incredible $300 billion plan to grow as quickly as possible. But they want to do it while protecting the city's culture, heritage, and natural environment. The centerpiece of this plan towers over the heart of the city: Aldar's appropriately-named Central Market. A 12-acre urban oasis filling 4 blocks, Central Market is a self-sustainable community for the modern ages, designed with a uniquely Arab point of view. Centered around the tallest residential tower on Earth, Central Market will be the first facility in the world that will take care of every spiritual, material, and relaxation need a person could have. It will also feature one of the world's tallest office towers, entertainment facilities for all ages, sky-high playgrounds for children, high-end shops, Edenesque gardens, hotels, as well as a reinvention of a traditional Arabian Souq.

The Port of Rotterdam in the Netherlands is the largest in the entire Western Hemisphere. Located less than 24 hours by road or rail from every EU capitol, it has for decades been the heartbeat of the European Union, and a cornerstone of the entire world's economy. But now, that cornerstone is in danger of collapse. With 90% of products today shipped by container, Rotterdam's container terminals are nearing capacity, threatening to become a trade bottleneck that could cripple a continent already devastated by recession. To make sure this doesn't happen, the Port of Rotterdam has launched the Maasvlakte 2 Project — an ambitious $4 billion plan to triple the port's container capacity by 2013. But in a country with literally nowhere else to build, that means undertaking the biggest land reclamation project in history, turning 8 square miles of the stormy North Sea into Europe's new gateway to the world. And it's much more than just earth-moving.