Two residential towers, dense with trees, will have their official opening later this year in downtown Milan. Blogger and critic Tim De Chant thinks it's high-time we stop planting trees on skyscrapers. Krulwich disagrees.

Kingdom Holding Company plans to finish the world's tallest building in Jiddah, Saudi Arabia. It would dwarf the Empire State Building and the current record holder which is in Dubai. The new building would climb 3,200 feet into the air but the developer did not say exactly when construction starts.

Tourists flock to Dubai just to see the Burj Khalifa, the world's tallest structure. Alain Robert went to climb it. The Frenchman, known as Spiderman, has scaled more than 70 skyscrapers.