A CAVE IS LIKE A HIDDEN MYSTERY. From shallow rock shelters and crevices to long underground caverns, our state is home to a fair number of these mysteries – 400 known caves. Some formed as 400 million-year-old sandstone dissolved, while others are the result of erosion, glaciers or even ancient volcanic lava tubes. Take an afternoon or day to discover these marvels.
1. Cave of the Mounds
2975 CAVE OF THE MOUNDS RD., BLUE MOUNDS
Discovered in 1939 – after a routine quarry blast – this National Natural Landmark near Blue Mounds features a 750-foot limestone cave lying 40-plus-feet underground. Various (harmless) bacteria have left a color palette of reddish brown, purple, gray and black, and added lighting reveals the otherworldly formations that look like melting frosting, dangling fangs and rippling coral. Some walkways and railings make it easier to navigate (self-paced tours can be done in an hour), and several side areas offer looks as well. COTM is also family friendly. Open daily 9 a.m.-5 p.m.
It’s time to pick your Milwaukee favorites for the year!
2. Crystal Cave
W965 WI-29, SPRING VALLEY
The state’s longest cave, at 1 mile, Crystal Cave lies 70 feet underground and takes an hour to tour. The caverns formed in dissolving dolomite rock formed at the bottom of an ocean over 450 million years ago. Bats dwell in the darkness among columns, stalactites and stalagmites, and the path sometimes requires a bit of ducking. You’ll see the tiny druzy crystals – sugar-like quartz formations – which give the cave its name. The property itself is a destination (kids and adults alike) with mini golf, trails, picnic areas and gem panning (digging). Open daily May 27-Oct. 31, hours vary.
3. Eagle Cave
16320 CAVERN LN., BLUE RIVER
Located near Blue River, this is Wisconsin’s largest cave formed by onyx, a sometimes-translucent mineral formation related to agate but showing banded layers. The cave opened to the public in 1938 and since then has expanded its attractions up top. Beyond the cave tours, activities include canoeing, mini golf and camping. Since the 1950s, there’s been a youth-group program allowing participants to spend a night in the caves. Guided tours held Thurs-Sun from Memorial Day to Labor Day.
4. Maribel Caves
15401 COUNTY RD. R, MARIBEL
Part of the Niagara Escarpment, the land in Cherney Maribel Caves County Park along the West Twin River north of Manitowoc felt the full grind of the glaciers, right down to the underlying dolomite. Then meltwater, springs and changing seasons produced cracks and caves in the cliffs. While some caves are open for self-guided exploration, the Tartarus Cave System, with its three entrances, along with Sinkhole and Spring Caves are only open for special tours. New Hope Cave, once filled with glacial till, is still gradually being excavated and can be toured the third Sunday of each month from May to October.
TIP: Underground caverns are damp and keep a cool temp of about 50 degrees, so pack a light jacket and wear sturdy shoes, not flip-flops!
Making Waves
A cave for those who crave light
NOT ALL CAVES will trigger claustrophobia and or even require a light. Cave Point, a fee-free Door County park near Jacksonport along the shore of Lake Michigan, shows a low dolomite cliff with partly submerged caves. Unlike others formed by dissolving minerals, these formations, visible from above, were carved by thousands of years of pounding waves. Sunlight can give the water a Caribbean hue, and waves often rebound with deep thuds, sending up plumes of whitewater. From the parking lot, it’s just a short walk to view the main cliffs. Open daily until 11 p.m.
