It took him just six hours to scale the tallest building in the world. Known for his "death-defying stunts"-- climbing skyscrapers around the world without safety equipment-- "Spiderman" Alain Robert has successfully added another notch to his belt. On Monday, the French urban climber topped the Burj Khalifa, the soaring glass tower in Dubai that's home to the Armani Hotel. "Le Spiderman" has scaled some 70 skyscrapers, but complied with safety regulations for this latest stunt, using a rope and harness. He even summited the tapered spire above the top floors of the building, 2,717 feet above the ground. Robert finished the climb in the darkness.