Strolling through Madrid is a great way to see the lavish Royal Palace, the 16th-century Puerta del Sol (Sun's Gate) marking the center of Spain, the old Moorish quarter of Moreria and much more.

The Mayan Riviera, Mexico's Caribbean coastline, is more than just the resort town of Playa del Carmen. Stretching from the fishing village of Puerto Morales to the biosphere reserve of Sian Ka'an, the area offers visitors a plethora of both eco-tourism and luxury destinations.

If watching the sunrise from atop a 10,000-foot volcano, swimming under waterfalls, hiking through craters and luxuriating on white-, red- and even black-sand beaches sounds like paradise, then Maui awaits.

The sound of music lures fans both of classical music and of Julie Andrews to Salzburg. Most sights are within walking distance of the city center.