Vanalden Cave

Contrary to the belief of non-Californians, the Golden State's most impressive features are geological. With such a mountainous region, caves are in abundance here. The Vanalden Cave may not be the most impressive but it is a bit of an oddity located near residential neighborhoods. The cave is surrounded by other hiking trails and a gorgeous view of the mountains and canyons. Even better, it's free, and you can bring your dog!