Standing at the base of the Great Pyramid, it is hard to imagine that this monument—which remained the tallest building in the world until early in this century—was built in just under 30 years.

So, what is the tallest building in the U.S. and what are its closest competitors? Each towering skyscraper tells a story. From New York's One World Trade Center to Chicago's Willis Tower ...

The tallest building in the world is the Burj Khalifa in Dubai, but the United States boasts plenty of vertical treasures that, like other architectural gems, are worth a sore neck. Now the Look ...