Explore the Lava Beds National Monument

A surreal landscape sculpted by molten earth, the Lava Beds National Monument contains volcanic tables dotted with cinder cones, pit craters and spatter cones, plus more than 700 caves. These odd features were formed 10,500–65,000 years ago, when the outer edges of the flowing lava began to cool, forming tubes. When the molten lava had stopped flowing, the hardened tubes were left behind. 

You'll also want to bring a good headlamp or flashlight — and a jacket — to explore the lava tubes. In summer, Siskiyou County can get quite toasty, with daytime temperatures of 100 ° F or more. But inside the lava tubes, it's remarkably cool; you might even find ice all year round.

You can explore the tubes on your own (there's no need for a spelunking experience, and kids can turn away from the thrill of entering these mysterious formations). And even though you're not going to cover a lot of ground, the trek can be a workout as you duck, twist, and even crawl through natural tights. It's easy to see how these caves were used as hiding places during the Modoc War of 1872–73, the only fight against Native Americans in CA.