Joshua Tree National Park - where two deserts meet - is a 800,000-acre (over 3,000 sq. km) wilderness where the two distinct ecosystems of "high" desert (Mojave) and "low" desert (Colorado) intersect. Its name comes from the Joshua trees in the Mojave section in the western half of the park. Mormon pioneers, crossing western deserts in search of the promised land, thought the stark trees looked like the upstretched arms of the Biblical Joshua. The park's flora and wildlife can be explored through horse and hiking trails. The mildest temperatures are in early spring when the desert wildflowers bloom or late fall. The Joshua Tree Music Festival takes place each May and October.