1. Florence, Italy: This city is a gallery of world-class art and architecture. A curator’s dream, the top sights include Michelangelo's David, Botticelli's Birth of Venus and Brunelleschi's Duomo. The town itself is a masterpiece: Its bridges, buildings, streets, towers and sidewalks were painstakingly constructed by stonecutters. With its warm trattorias, upscale shops and small luxury hotels, the city is a Tuscan treasure.

2. Buenos Aires, Argentina: The country’s capital exudes an air of the exotic, smoky and mysterious that is embodied by its tango salons and sophisticated café life. Now recovering from a period of economic crisis, the city has been called the Paris of South America for its neoclassical buildings on tree-lined boulevards. The Museo del Arte Latinoamericano de Buenos Aires (MALBA), created by young Argentinean architects in 2001, is a symbol of the city’s modernity.

3. Bangkok, Thailand: The yin-yang relationship between the old and the new is ever present in Thailand's capital city. Its 10 million residents strive to preserve the past (the Grand Palace) and expand for the future (with high-end shopping and luxury hotel developments that are among the best in Asia). The authenticity of the city’s centuries-old culture can be discovered in its narrow alleyways, away from the grinding traffic, where visitors can find silk and handicrafts by local artisans.

4. Rome, Italy: Once you see the Colosseum, venture to the Via Veneto, visit the Vatican and marinate in the history, art and architecture of the capital, indulge in Rome's la dolce vita. After the sunset casts its colorful glow on the Eternal City, romance fills the night air (take an after-dinner stroll with a loved one to Trevi Fountain or hang out at a surprising hot spot, the Pantheon).

5. Sydney, Australia: The 2000 Summer Olympics introduced Sydney to much of the world, but it has long been Australia's capital for sun and sand. In addition, the city’s artistic side is defined by landmarks such as the Sydney Opera House, Sydney Cove and Sydney Harbour Bridge. An international beacon of the good life, this Southern Hemisphere city pulses with a thriving arts scene, fine restaurants and world-class hotels.

6. New York City: Millions of visitors come to Gotham City for an array of reasons. Those who love the arts can watch Broadway stars, glimpse masterpieces at the Met or escape with an opera at Lincoln Center. Foodies may choose from countless menus and mingle with the culinary artists—from mom-and-pop deli owners to star restaurant chefs. Famous Manhattan buildings are also worth seeing firsthand: Stand amid the throngs of sightseers below Times Square’s neon billboards or peer down at the Monopoly-game like cityscape from atop the Empire State Building.

7. Udaipur, India: Passage to Udaipur admits one to the “City of Sunrise.” This destination—renowned for its temples and utter serenity—is known as India's most romantic city. With 16th-century architecture and timeless beauty, sample itineraries of tranquility might include a cruise on the calming waters of Pichola Lake or an afternoon meandering through fortresses and palaces.

8. Istanbul, Turkey: Straddling Europe and Asia, Istanbul is a city that represents a crossroads of civilizations. The city that connects continents also embraces its differences most tangibly at the labyrinthine Grand Bazaar. Just as complex and monumental are Istanbul’s sights, all constructs of 2,500 years of civilization. A visit to Topkapi Palace of the Ottoman dynasty and the Hippodrome built by the Romans should top your historical itinerary.

9. San Francisco: The City by the Bay’s Victorian neighborhoods and charming streetcars are just some of its historic attractions. Its modern-day delights include attending a tasting at one of the trend-setting restaurants or browsing contemporary art at the De Young Museum. The city is a living postcard, with backdrops such as the majestic Golden Gate Bridge and colorful, bustling Chinatown. But what brings back many visitors is its laid-back vibe, visible in its lively café and bar scene.

10. Cape Town, South Africa: Long hailed as an up-and-coming tourist destination, Cape Town continually wins “best of” awards. A mixture of European influences and African ancestry, this town celebrates the land’s many bounties with restaurants that pair entrées with cabernet sauvignon from the surrounding wine country. Activities may include escaping to a safari at a game refuge, strolling through the lush Kirstenbosch Botanical Gardens, taking a ride on the Table Mountain Aerial Cableway or playing in the surf off Cape Point.