Summer is here, and hikers are exploring Wyoming's greatest trails. But it's hot up on those trails. Another great place for a walk, which is much cooler, would be underground—in a cave.

Wyoming has some of the greatest caves in North America. The Horse Thief Cave in the Big Horn Mountains, for example. No one needs to wonder how it got its name.

Many of these caves are simply open to the public. Some are on part service land and you'll need to register to get in. Either way, if you are going, let someone know, and never travel alone.

Some are closed to the public:

The Secret Cave, as it is called is an 80-foot drop and filled with the bones of ancient animals. The area is being studied by experts from all over the globe.

But, as seen in the video below, you and your entire family can visit the Tongue River Cave:

The Tongue River Cave is mostly easy to get in and out of and is well marked by anyone who went before you.

If you are wondering, 'what if there is a bear in there or a mountain lion?' Caves like the Spirit Mountain Cave, in the video below, actually have gates on them to keep the animals out but let the humans in.

Finally the Sinks Canyon Cave, in the video above, where you can find fossils and bones all on your own. The video shows a family taking their kids down below to explore. It is safe, but you still need to take someone with you who knows what you are doing. Make sure to tell people where you are going and how far you will be gone, just in case.

There are several more caves to be explored. So let's just say that if hiking out of the heat is something you would like to try, here are a few maps of Wyoming's caves to help you find one near you.

Good luck and be safe.