Bonnechere Caves give explorers a rarely seen glimpse into early days of the Earth. Encased within the limestone walls lie fossils of coral and other marine life that are estimated to be between 400 and 500 million years old, predating both dinosaurs and the Walkman. Despite their advanced age, the caves were unknown until 1955, when the subterranean channels of the Bonnechere River were cleared, revealing the ancient passageways carved out by eons of currents.

Today, tour guides lead explorers of all ages into the caves' earthly halls, home to a sinkhole, a waterfall, and stalactites—rock icicles that form at a rate of 1 cubic inch per 150 years—all illuminated by electric lights. Occasionally, a snoozing bat makes an appearance or steps out to take in his trash cans. To heighten the experience, guides sometimes host special events such as fossil hunts, and visitors can also take advantage of the picnic grounds just outside the caves, as well as activities such as dining, golf, and museums in the surrounding area.