Saddle Road (state/county route 200) is the closest thing to a cross-island highway on the Big Island. It is a famously bad and dangerous road despised by most rental car companies, which generally prohibit tourists from taking their vehicles on the road (Harper's, in Hilo and Kailua-Kona, is the most notable exception), making this highway perhaps the only paved state highway in the United States that is off-limits to most rental cars. The road was built during World War II to provide access to an Army training area in the Big Island's interior, and at least the western half feels like it hasn't been maintained or improved much since. However, it is an interesting road for intrepid travelers, with its close-up views of the Mauna Kea and Mauna Loa volcanoes and the lava fields covering the "saddle" between the two. It also takes travelers to side roads to the observatory complex on the Mauna Kea summit, and a weather observatory high on the north slope of Mauna Loa (which also is one of the two trailheads for the arduous hike to the Mauna Loa summit).