A corner of Halong Bay.

"Ha Long Bay, in the Gulf of Tonkin, includes some 1,600 islands and islets, forming a spectacular seascape of limestone pillars. Because of their precipitous nature, most of the islands are uninhabited and unaffected by a human presence. The site's outstanding scenic beauty is complemented by its great biological interest," Newsweek reported. The top three sites are Cambodia’s Angkor Wat, Italy’s Venice, and Australia’s Great Barrier Reef.