Summer lake visitors can find themselves longing for cool air—hard to come by at Lake Shasta in August! Perhaps the best natural air conditioning in the region can be had inside the Lake Shasta Caverns

During the summertime, tours leave every half-hour starting at 9 a.m.

When your tour is called, you’ll walk down to the boat launch and board a broad, flat-bottomed ferry with plenty of bench seats and a canopy. As you take the quick ride across a narrowish section of the lake, your driver will regale you with tales of the caverns. Pay attention; though there isn’t a test, the tour is more fun if you know more about what you’re looking at.

At the dock (where boaters can meet their tour groups if they prefer), you’ll get on a bus and take a staggeringly steep drive up 800 feet to the cavern entrance. The road permits some fabulous views out over the lake and all the way up to Mount Shasta.

Your cavern tour guide will meet you at the entrance, then lead you into a manmade tunnel. You’ll head up a whole bunch of stairs and into the series of natural limestone and marble caverns. The guide will describe the amazing formations that spring from the walls, the ceiling, and even the floor. The guides have spent a lot of time in the caverns and have found shapes within the formations that they’ve named.

The cathedral size of most of the cavern areas and the railed walkways help to remind visitors not to touch the delicate stalactites, drapes, pancakes, and ribbons of “cave bacon” that decorate each space. You’re welcome to bring a camera to try to record the marvels you’ll see here, but memories often provide better lighting.

Both kids and adults enjoy the tour of the Lake Shasta Caverns, but you’ll want to keep an eye on younger children throughout the trip for their safety. No matter how hot it is outside, bring a jacket or sweater for your tour; the caverns remain a constant 50-something degrees all year long. While the tour isn’t incredibly strenuous, you need to be able to walk and to climb over 100 stairs at a time.