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.

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.

If you visit Honolulu simply for the wide Pacific beaches, the striking views of Ko'olau's pali (cliffs) and the laid-back "aloha" feeling, you'll be missing out on much this city has to offer.

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.