Last weekend, a ceremony marked the laying of the last beam on the Shanghai Tower, China's tallest building. The 632-meter building, located in the heart of Shanghai's financial district, is scheduled to open its doors in 2015.

Little noticed amid the hubbub was the groundbreaking weeks earlier in the city of Changsha of Sky City, a skyscraper that, when completed, will dwarf Shanghai Tower. At 838 meters, it will be the world's tallest building, overtaking the current No. 1, Dubai's Burj Tower, which stands 828 meters tall.

These two buildings are part of a Chinese boom in mega-building construction; two other notable structures include a 606-meter building in Wuhan and a 660-meter skyscraper in Shenzhen. The construction crane continues as China's de facto national bird.