Four Admission Tickets for the Polar Caves in Rumney, NH. 

"Polar Caves is home to nine granite caves you can duck, squeeze and shimmy through! How are our boulder caves different from limestone caverns? Granite caves are formed, not by flowing water, but from boulders that have been deposited by a glacier. The negative space between the boulders form passageways to explore."

https://polarcaves.com/