Well worth a visit. Even if you're not that interested in history, the tales of tragic love stories and breakout attempts will stay with you well after your tour.

"When in Rome, do as the Romans." That classic advice leads to a wealth of options: Should you follow Augustus and Caesar, whose Rome is filled with spectacular ancient structures?

For a bird's-eye view of London, take a spin on the London Eye, the Ferris wheel overlooking the Thames. Don't miss landmarks like Big Ben, the Tower of London, St. Paul's Cathedral and the Globe Theatre.