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.

Vietnam's bustling largest city sets the cultural and economic pace for the country. The former Saigon boasts charming French colonial architecture and wide boulevards, usually thronged and choked with traffic. Taxis are an option for seeing the sprawling city. The War Remnants Museum shows the Vietnam War through Vietnamese eyes. Don't miss the impressive Jade Emperor Pagoda. Go to the frenetic Ben Thanh Market for food, flowers or frogs. Tour through the Mekong Delta, past rice paddies and houseboats.

Perched on the banks of the wide Swan River, between the Indian Ocean and the sands of the Nullarbour Desert, Perth is one of the world's most isolated cities, yet still boasts an active beach scene and smokin’ nightlife. Family-friendly Cottesloe is brimming with swimmers, surfers and snorkelers. Head north to Scarbourough for a spirited beachside club scene. Coo at cute marsupials on ferry-accessible Rottnest Island, and don’t miss the views from King's Park and Botanic Gardens.

Bangkok is full of exquisitely decorated Buddhist temples—as you go from one to the next you’ll be continually blown away by the craftsmanship and elabourate details. But if you’d rather seek enlightenment in a gourmet meal, or dance the night away, you’ll also enjoy Bangkok—the restaurant and nightclub scenes here are among the best in the world.

Lovely, laid-back Melbourne has something for everyone: family fare, local and international art, haute boutiques, multicultural dining, Australian and Aboriginal history, spectator sports, and pulsing, swanky nightlife. Cruise on the free City Circle Tram loop to check out unique attractions like the Royal Botanical Gardens and the Healesville Sanctuary, which buzzes with local animal species.