About 45 minutes west of Panama City, the 11-mile Pipeline Road near Gamboa cuts through the jungle along the path of a never-used World War II oil pipeline. The first four miles along the narrow trail are almost flat, but the terrain grows hillier farther down. It has the reputation of being the best birding spot in the Americas but also makes for an easy ramble through the forest. After the first free mile or so, there's a $5 entry fee.