The Pantheon, Historic Center Of Rome

"From its blunt and windowless exterior, the Pantheon is hardly the most dramatic monument on UNESCO's list, or even in Rome, whose World Heritage sites include the Forum, the Colosseum, the Vatican, and more. But step inside and you realize that this Roman temple—still standing after almost 1,900 years—has the most perfect proportions of any building on earth. The rotunda is 141 feet in diameter and 141 feet in height. A cylinder of light beams through a hole at the top of the dome, dramatically lighting the entire space. (Rain flows into small holes in the original marble floor and then out through ancient Roman pipes, while most of the room stays dry.) The Pantheon [was consecrated] in 609, and when I first visited it, an organist was practicing Ave Maria. That's why I love that hymn."

—Ed Wetschler, executive editor, Tripatini.com