Tourism serves as an economic engine for Chula Vista. The city has numerous dining, shopping, and cinema experiences. As with many California cities, Chula Vista features many golf courses. Some of the city's notable attractions included the Chula Vista Nature Center, Otay Valley Regional Park, North Island Credit Union Amphitheatre, OnStage Playhouse, the Chula Vista Marina, Aquatica San Diego, and the U.S. Olympic Training Center. The Nature Center is home to interactive exhibits describing geologic and historic aspects of the Sweetwater Marsh and San Diego Bay. The center has exhibits on sharks, rays, waterbirds, birds of prey, insects, and flora. Otay Valley Regional Park is located partially within Chula Vista, where it covers the area of a natural river valley.