Palm Jumeirah

Over the last decade, the city of Dubai has experienced phenomenal growth, most of it concentrated on 37 miles (60 kilometers) of coastline bordering the Persian Gulf. Unfortunately, all of the high-rise apartments, skyscrapers and hotels stand shoulder to shoulder on the shore, leaving little room for new development. To solve that small problem, Nakheel Properties, a government-backed real estate developer, decided to extend the Dubai shoreline by building three man-made landmasses known as the Palm Islands.
How do you pull off such a feat? You pile up tons and tons of sand and rock until an artificial island emerges in the ocean. Workers dredged up more than 3 billion cubic feet of sand to build Palm Jumeirah, the first of the three islands [source: Dowdey]. But they didn't simply heap the stuff into a big mound. Instead, they created an archipelago in the shape of a palm with a trunk stretching 1.24 miles (2 kilometers), a crown made up of 16 fronds and a surrounding crescent. They used GPS data to make sure the structure retained its symmetry throughout construction.
In 2013, Palm Jumeirah remains the largest man-made island in the world -- at least until its companions rise from the sea. When it's completed, Palm Deira will be even bigger, occupying approximately 18 square miles (47 square kilometers) of land reclaimed from the Persian Gulf.