Glamorous Santorini, in the southern Aegean's Cyclades islands, curves round a giant lagoon, a caldera left by a volcanic eruption.

With its ultramodern skyline, it's easy to forget that Dubai, part of the United Arab Emirates, was once a small town of Bedouin traders.

Mountain views, raucous nightlife and a C-shaped bay with a plethora of beaches make Acapulco a more upscale, yet reasonably priced, escape than its spring-break cousin, Cancun.

Historic and modern, European and Asian — that's Istanbul. The city at the junction of two continents is home to ancient structures like the Hagia Sophia and the Blue Mosque in the Old City, as well as modern businesses, hotels, restaurants and nightlife in the New City.