China already has the worlds largest population (1.3 billion), the worlds most polluted cities (pollution-related ailments are the leading cause of death), and plans to build some of the world's tallest structures (the Shanghai World Financial Center is still under construction) to rival the current record holder, Taipei 101. This weekend, China will come one step closer to obtaining its next superlative when the last structural concrete is poured for the Three Gorges Dam.  When it comes online fully in 2009, it will be the largest hydroelectric dam in the world.

Although the officially reported budget for the dam is $25 billion, estimates of the actual cost are as high as $100 billion, which would also make it one of the worlds most expensive construction projects. Plus, the $100 billion does not factor in the dam's secondary costs, which include relocation expenses for the million people displaced by flooding, the loss of fertile land, bribes and corruption, and extensive environmental damage. The most environmentally destructive human construction, perhaps? Thats a record no ones in any rush to publicize.

Google Earth's coverage of the region is disappointingly low-res, but as it always does, NASAs Web site comes through with a giant satellite photo of the region. —John Mahoney

Related: "How High Will They Build?"

IN SEPTEMBER 2001, New York developer Donald Trump was dreaming of building the world's tallest skyscraper, a 2,000-foot mega-tower that would return the record to America from Malaysia, where it had been lost, though not without controversy, to the twin Petronas Towers. Trump's people met in Chicago with architects from the legendary firm Skidmore, Owings and Merrill, which had designed the magnificent John Hancock Center in that city, with its bridge-like exoskeletal steel ribs, and the Sears Tower, which had been dethroned by Petronas in 1996.