Laurel Caverns, the largest cave in the northeastern U.S., is set to become Pennsylvania's 125th state park. The cave, currently owned by the Laurel Caverns Conservancy, will be donated to the state.

At age 75, Vadevino Alano keeps up a brisk pace as he strides through the forest on the way to the Armadillo’s Den — a spectacular cave in southern Brazil. When he reaches the cave’s opening ...