About 130km west of Ottawa en route to Algonquin Provincial Park, these caves are some of the world's finest examples of solutional caves (dissolved out of solid rock by acidic waters). Formed 500 million years ago from the floor of a tropical sea, the dank passages feature a haunting collection of fossils including a prehistoric octopus. Learn about speleology (the study of caves) on the humorous tour, which details the site’s quirky history.

Nimble guests will enjoy squeezing through a few extra-narrow, damp passages. The caves are signposted from Hwy 60 at Douglas and Eganville.