Swift streams and waterfalls continue to carve these vertiginous and rugged valleys as they pour down into the sea. One of the most stunning wilderness areas on Earth, it also contains ancient Hawaiian ruins of graves, temples, house platforms and terraced fields. The fear factor—and actual dangers—increase past the initial 3.2-kilometer (two-mile) path to Hanakapiai Beach. Only experienced hikers in good condition and with proper gear should venture further along the famous Kalalau Trail. However long you trek, stay on the main path and pack out what you brought in.