Off I-5, 48 miles North of Redding. Thrown up by volcanic activity 200 million years ago, the stark and dramatic granite spires of Castle Crags State Park loom above I-5. These forbidding 4,000-ft-high extrusions offer a stiff challenge even to experienced rock climbers. Several relatively easy trails pick through the lower elevations where the park’s trees – oaks, firs, dogwoods and cedars – are clustered. There is swimming and fishing in the Sacramento river, as well as lots of scenic hiking and campsites – www.parks.ca.gov.