Ross D. Franklin, AP
What compels humankind to keep building upwards? Competitive spirit? Capitalist drive? Whatever it is, from a tourism perspective at least, heart-stopping views are a big draw. It seems lofty lookouts, lounges and other precarious perches can provide the high point of a vacation. And the dizzying distances between the ground and the top of the world's vertigo-inducing structures -- from a skyscraping observatory at the top of the world's highest tower in Dubai to a 55th-floor infinity pool in Singapore -- just keep increasing. Where it will stop, no one knows. From observation decks to sky-high parks -- here are ten top places built for a bird's eye view.