Over the centuries, many cultures have added their mark to this prized piece of land. Today, you can experience those influences firsthand by exploring Istanbul’s mahalles (neighbourhoods). From the holy sites of Sultanahmet and the 19th-century European elegance of Beyoğlu to the high fashion of Nişantaşı, the vibrant café society of Kadıköy and the football-loving streets of Beşiktaş, it’s easy to see why travellers say that Istanbul isn’t just one city, but many cities within one.

Cairo’s an ancient city that also happens to be a modern metropolis—it’s one of the biggest cities in the Middle East and has the traffic and noise issues to prove it. But as long as you’re not looking for solitude, Cairo—the City of the Thousand Minarets—is a splendid place to explore Egyptian history and culture. (Editor's note: Our list was compiled before political unrest prompted many countries to issue travel warnings for Egypt. If you're currently planning a trip to Egypt, please consider the risks and monitor your government's travel alerts.)

It’s nicknamed the Eternal City for a reason. In Rome, you can drink from a street fountain fed by an ancient aqueduct. Or see the same profile on a statue in the Capitoline Museum and the guy making your cappuccino. (Which, of course, you know never to order after 11 am.) Rome is also a city of contrasts—what other place on earth could be home to both the Vatican and La Dolce Vita?

Move over, Haussmann and l'Enfant. Beijing's urban planner beat you by a couple of centuries. His name is Kublai Khan. Here, you'll find a wealth of history, both ancient (the Hall of Preserving Harmony, Summer Palace, Forbidden City) and more recent (Chairman Mao Memorial Hall, Tienanmen Square). For the best market experience, choose the Dirt Market over the touristy Silk Market.

Famed throughout Asia for its heady mix of eastern cultures, Penang Island is Malaysia’s prime melting pot. Roadside vendors serve some of the world’s best street food; its national parks offer white-sand beaches and wildlife; and UNESCO-listed George Town is full of colorful heritage houses.

China’s third-largest city is the capital of Guangdong Province and a thriving commercial centre. Its location on the Pearl River and proximity to Hong Kong has made Guangzhou a strategic port for centuries. Glimpse old temples and gleaming steel towers on an architectural tour. Visit one of four Chimelong theme parks for thrills and chills. Once called Canton, Guangzhou is considered the home of traditional (read Cantonese) “Chinese food.” Foodies will find more restaurants per capita here than anywhere else in China.

Hong Kong's a great city for an adventurous eater. Stop at a street vendor for fish balls on a stick or stinky tofu. Bakeries offer wife cake, pineapple buns and egg tarts. Or opt for as much dim sum as you can eat. If you're tired of local and regional Chinese specialties, check out upscale offerings from some of the world's top chefs, like Joel Robouchon and Alain Ducasse.

Singapore is known as a bustling metropolis that also happens to be one of the cleanest and safest cities of its size in the world. (Just make sure you heed the local laws—something like spitting in the street might merely be considered rude in your hometown, but here, it carries a severe penalty.) You'll find historic sites like the Thian Hock Keng temple, superlative shopping (including gargantuan malls) and numerous beaches.