This pie-shaped area of 1.6 million acres, situated near the state line between Los Angeles and Las Vegas, is punctuated by precipitous mountain ranges, dry lake beds, lava mesas, cinder cones, granite domes, sand dunes and limestone caverns. The rugged landscape, where elevations range from 900ft to 7,929ft, is home to some 700 species of plants and nearly 300 species of animals. A threadbare carpet of creosote bush covers the lowlands, while open forests of pine and juniper, and extensive stands of Joshua trees thrive in higher, cooler areas where cattle still graze the range. The renovated Kelso Depot is now the Visitor Center for Mojave National Preserve, with nature and history exhibits about the depot and the park. Among the sights in the park are the volcanic cinder cone of Amboy Crater and the 30 ash, parasitic and breached remnants of the Cinder Cone Lava Beds. Both are designated National Natural Landmarks. Kelso Dunes are some of California's highest sand dunes, measuring 560ft above the valley floor. Concealed within a desert mountainside are Mitchell Caverns, part of the Providence Mountains State Recreation Area. These six limestone caverns reveal beautiful, colorful and curious dripstone and flowstone formations, including stalactites, stalagmites, cave columns, cave shields, "lily pads" and coral pipes. They may be viewed by guided tour only.