formations. Lake Manly once covered the valley to a depth of . The salt in the Devil's Golf Course consists of the minerals that were dissolved in the lake's water and left behind in the Badwater Basin when the lake evaporated. With an elevation several feet above the valley floor at Badwater, the Devil's Golf Course remains dry, allowing weathering processes to sculpt the salt there into complicated formations. Through exploratory holes drilled by the Pacific Coast Borax Company, prior to Death Valley becoming a national monument in 1934, it was discovered that the salt and gravel beds of the Devil's Golf Course extend to a depth of more than . Later studies suggest that in places the depth ranges up to . Devil's Golf Course can be reached from Badwater Road via a gravel drive, closed in wet weather. It should not be confused with an actual golf course in Furnace Creek, also in Death Valley. Eureka Valley and Sand Dunes Between the Last Chance Range and Saline Mountains is the graben Eureka Valley. Sand dunes cover 3 square miles (8 km2) of Eureka Valley, rising 680 feet (207 m) as one of North America's tallest dunes. As sand moves down the dune face it produces a booming noise, known as singing sand phenomenon, due to the small grain size and loose, dry packing. Endemic species include the Eureka Dune Grass, the Eureka Evening Primrose and the Shining Locoweed. Furnace Creek Furnace Creek is a spring, oasis, and village that sits on top of a remarkably symmetrical alluvial fan. The main visitor center of the park is located here as well as the Oasis at Death Valley resort complex. Controversy surrounds the use of Furnace Creek water to support the resort (complete with a swimming pool) and nearby facilities, including a golf course. The scarce springs and surrounding lush oases support thriving plant communities and attract a wide variety of animals. As the resort grew, the marshes and wetlands around it shrank. The highest temperature in North America was recorded at Furnace Creek Ranch (134 °F or 57 °C). The Furnace Creek Fault runs through this part of Death Valley. Hells Gate Hells Gate is a point of interest located in Death Valley National Park, at the intersection of Daylight Pass Road and Beatty Road. There is a parking area and hiking paths. Mesquite Flat Sand Dunes The Mesquite