Denver is the largest city in Colorado, the state capital. It lies at the foot of the Rocky Mountains at the junction of the South Platte River and Cherry Creek. Denver is an important communications, transportation, manufacturing, and agribusiness hub. Telecommunications and biomedical technology are two of the largest industries; construction, real estate, and retail trade are among the fastest-growing industries. The city is also home to many environmental organizations, including federal government agencies such as the Environmental Protection Agency and the National Oceanic and Atmospheric Administration. The city's tourist attractions include the Denver Zoo, the Six Flags Elitch Gardens amusement park, the Red Rocks Amphitheatre, the Coors Brewery, and nearby Rocky Mountain National Park.