The bubbling, turquoise crystalline pools of Plitvice Lakes National Park comprise one of Croatia's most popular tourist destinations. Just a two-hour drive from Zagreb, the national park offers 50 acres of forest and lake. In winter, it's a wonderland of frozen waterfalls. In summer, the park is lush with greenery. Wooden walkways and hiking trails traverse the porous karst limestone. This World Heritage Site is a veritable wildlife haven, home to everything from birds to boars and even bears.