Concierge.com's insider take:
This 1.4-million-acre jungle preserve, which separates Panama from Colombia, is the country's biggest draw for nature-lovers—and like a mini–Amazon rain forest in its diversity of terrain and wildlife. Several hundred bird species and more than 100 species of mammal (including wild pigs and capybaras—the world's biggest rodents) live among the cloud forest, mangroves, and winding riverbeds. Ancon Expeditions has treks for small groups lasting from three days (very easy, traveling mostly by boat) to five days (quite challenging, with three to five hours of hiking each day). You arrive by small plane from Panama City then head deep into the wilderness. Along the way you encounter villages inhabited by the indigenous Embera people, where your guide will stock up on supplies. Guests on shorter trips stay overnight in the tour company's own rustic cabins overlooking the Gulf of San Miguel; those on longer trips stay in dorm-style field stations and screened tents (507-269-9415; www.anconexpeditions.com).