Missouri

If you're heading to the state of Missouri go to Meramec Caverns watch the: Reflection & Light Show While most people come for the Jesse James history, the real showstopper is the Mirror Room. The water is so still and clear that it creates a perfect reflection of the stalactites above, making it look like a bottomless canyon.

• Fun Fact: If you're into photography, this is where you'll get your best shot—hold your phone low to the water to capture the "infinite" effect.

• The Big Finale: Don't duck out early! The tour ends with the "Greatest Show Under the Earth," a classic, patriotic light show projected onto the "Stage Curtain" (one of the largest cave formations in the world). It’s a bit kitschy, but seeing the cave walls shift through vibrant colors is a unique experience you won't find in wild caves.

What to Avoid

• Avoid wearing "flip-flops" or "open-toed shoes": The cave stays a constant 58°F (14°C) and is naturally damp. The walkways can be slick and muddy in spots. Wear comfortable, non-slip walking shoes or sneakers to avoid a wipeout.

• Avoid bringing a stroller: While the paths are paved, there are several sets of stairs and some steep inclines that are not stroller-friendly. If you have a little one, a front-loading baby carrier is the way to go.

• Avoid the "Bathroom Blunder": There are no restrooms inside the cave, and the tour takes about 1 hour and 20 minutes. Make sure everyone in your group hits the facilities in the gift shop area before the tour departs.

• Avoid touching the formations: It’s tempting, but the oils from your skin can "kill" a cave formation by preventing the minerals from continuing to build up. Keep your hands to yourself so the cave keeps growing for another million years!

Pro-Tip for Summer Visitors: If the cave tour isn't enough, check out the Caveman Zipline on-site. It takes you right over the Meramec River and is a great way to dry off if you’ve been doing a float trip earlier in the day.