The Pan-American Highway passes through many diverse climates and ecological types ranging from dense jungles to arid deserts and barren tundra. Some areas are fully passable only during the dry season, and in many regions driving is occasionally hazardous. The Pan-American Highway system is physically mostly complete and extends in "de facto" terms from Prudhoe Bay, Alaska, in North America to the lower reaches of South America. Several southern highway termini are claimed, including the cities of Puerto Montt and Quellón in Chile and Ushuaia in Argentina.