August 2-8, 2026

Ever wanted to see inside our big red barn? Come celebrate Cave of the Mounds’ 87th birthday with us this August during our Discovery Days celebration!

Cave of the Mounds was discovered on August 4, 1939 after a quarry blast opened the ceiling of the cave. Ever since that happy accident, we’ve welcomed millions of visitors into the cool cave air. For the first week of August, we invite you to join us in celebrating this one-in-a-lifetime discovery.

Cave tours will run as usual while we’re open, and guests will be allowed into the Historic Brigham Barn to explore its largest room and check out the artifacts and activities within. The barn is only open to guests for one week out of the year, so don’t miss your chance to look inside!

We will also host guided hikes during the day, taking you and your friends and family along our Karst View Trail as it’s interpreted along the way.

No purchase necessary to explore the grounds. Cave tickets available at regular rates.