Out on the western coast of Oahu, these four man-made coves are some of the island's most peaceful and beautiful places to swim. Known collectively as the Ko Olina Lagoons, the small inlets use giant rock levies to protect the shores from crashing waves and are accessible from the JW Marriott Ihilani Resort & Spa.

Read more: How to Plan a Trip to Hawaii
 

Though the Panama Canal is undoubtedly the country's most important man-made attraction, the Amador Causeway, a three-and-a-half-mile causeway spanning four islands (Naos, Culebra, Perico, and Flamenco), is a close runner-up. Built from rock excavated during the construction of the canal, the single-lane road is flanked by a bike path and offers stunning views.

Read more: 5 Ways to Explore the Panama Canal (Without Taking a Cruise)

There are plenty of ways to spend money in Dubai, but a leisurely stroll around Palm Jumeirah (one of three artificial palm-shaped islands found in Dubai), shouldn't be one of them. Allow yourself to be amazed at the sheer size of the island, which contains over a dozen resorts and hotels, most notably, the fantastical Atlantis, The Palm.

Read more: Dubai, A Surprising Wellness Destination You Didn’t Know About
 

The Dutch region of Flevoland was drained in two stages in 1955 and 1968, leading to the creation of a lake-surrounded "island" that is known as Holland's youngest province, incorporated in 1986. It's also the world's largest artificial island. Visitors show up here for the region's stunning nature reserves, botanic gardens, and an aviation museum.

Read more: The Sweet Spot: Amsterdam
 

Full disclosure: You can't swim unless you're a guest. But if you're anywhere nearby, it's hard to miss the pool at Chile's San Alfonso del Mar resort. Known as the largest outdoor pool in the world, the giant basin spans 20 acres and is filled with seawater, offering the luxury of space without the worry of being carried out to sea. Don't be surprised if you see a few sailboats drifting by; the surface area is so large, the hotel offers paddling and sailing as a way for visitors to experience the pool.

Read more: Food, Wine, Art, and Ocean Views in Vina del Mar, Chile
 

In 2013, a mammoth office-retail complex opened in Chengdu, China that, with 18 million square feet of floor space, easily surpassed the mark for the world's largest building. Inside the New Century Global Center, visitors can choose from an array of shops, an IMAX theater, two hotels, and even an artificial beach with actual waves (entrance to the mall is free, though there is a beach admission cost of $30 per person).

Read more: A Sleek Hotel in the Heart of Historic Chengdu, China
 

Singapore's architectural masterpiece, the Marina Bay Sands, may be a man-made wonder, but the city's nearby Sentosa Island is a resort destination packed with nature parks, an aquarium, a Universal Studios theme park, and Singapore's finest (and, well, only) beaches where you can swim. Though not noticeable at first, the beaches are all artificial, composed of sand hauled in from neighboring Indonesia and Malaysia.

Read more: Save, Spring, Splurge: Singapore
 

Hugging Copenhagen's eastern coast along the Øresund is a tiny strip of land known to locals as Amager Beach Park. The artificial island spans only 1.2 miles in length, but its total beach area is almost three miles (all free and open to the public), with wide sandy stretches, a promenade, game areas, a marina, and a lagoon with rowing lanes. The whole island is connected to the mainland by three separate bridges, allowing easy access for day visitors.

Read more: 7 Top Things to Do in Copenhagen