At 3,583 acres Forestville/Mystery Cave is one of the largest state parks in southern Minnesota, and it's rich in attractions. More than 24,000 people toured Mystery Cave last year, setting a new attendance record for the state's longest-known cave, discovered in 1937. With 17 miles of horse trails and an equestrian campground, this state park lures more horseback riders than any other. Add the historic town of Forestville, three spring-fed trout streams, 20 miles of hiking trails, 96 campsites, and five camper cabins, and the drawing power becomes clear.

Historic Forestville, operated by the Minnesota Historical Society, springs back to life from spring to fall. Once a thriving settlement of 100 residents, Forestville withered after being bypassed by the railroad. Re-enactors show visitors a time when the general store stocked everything from calico and coffeepots to tobacco and tin mousetraps.

No matter what draws park visitors, they best not pass up a guided tour of the cave. The park's karst limestone landscape creates ideal conditions for cave formation. The underground passages extend 13 miles. Cracks in limestone have been enlarged by ground water, forming a cave. When water drips into the cave, it deposits minerals that form stalactites on the ceiling and stalagmites on the floor.

Interpretive supervisor Warren Netherton says visitors "have an opportunity to experience the place where water goes—from where it lands on the surface and sinks into the ground, to the point where it reaches the aquifer down below."

The karst landscape favors trout streams. Few streams in Minnesota boast more fish than the South Branch of the Root River—nearly 5,000 fish per mile, mostly naturalized brown trout. Canfield and Forestville creeks add more angling opportunities. "If anything," says Netherton, "those streams are underfished." Park visitors may check out loaner fishing gear.

Late spring is a colorful time in the deciduous forest. False rue anemone and bluebells festoon the forest floor. So do trout lilies, wild ginger, and Dutchman's breeches. Returning migrant songbirds—some passing through, some staying to nest—fill the park with song and flashes of color. Look and listen for redstarts, kingfishers, phoebes, peewees, ovenbirds, and catbirds.

"The warblers love the oaks," says Netherton. "The key is to get out there before the leaves come out so you can still see them. They'll be singing up a storm."