Lost Sea Adventure

This trek through Craighead Caverns begins in the gift shop, where you venture down a bright tunnel. Once inside the cavern, guests take a winding half-mile walk. Lights illuminate an otherworldly landscape. One minute you’re ducking under rock formations, the next you’re gazing in amazement at a wide-open chamber. The walk takes you to an underground lake, where guests board glass-bottom boats that slowly cruise the 4½ acre lake as hefty rainbow trout swim underneath. Peer over the edge and you might get a better look at the 30-ton rock that fell into the lake some 2,000 years ago.

140 Lost Sea Road, Sweetwater, Tenn. 423-337-6616, thelostsea.com.

Tennessee River Gorge

About 27 miles of the Tennessee River snakes through 27,000 acres of the rolling geography of the Cumberland Mountains. The gorge begins about 5 miles downstream from the heart of downtown Chattanooga, winding all the way to Hales Bar Dam Marina in Guild, Tenn., near Nickajack Lake. There are lots of photo ops: Blankets of lush, dense green cover the gorge’s mountains during warmer months. Come fall, the flora morphs into rustic bouquets of brown and orange. Hikers often explore scenic trails located at such spots as Raccoon Mountain, Prentice Cooper State Forest and along the Cumberland Trail.

Tennessee River Gorge Trust, 1214 Dartmouth St., Chattanooga. 423-266-0314, trgt.org.

Brimstone Recreation

With nearly 20,000 acres, Brimstone, in northeast Tennessee, has more than 300 miles of off-highway vehicle trails. Rent an all-terrain vehicle and plan your off-road adventure with the help of an online map. Trails range from easy terrain for newbies to more challenging turf for veterans. Camping near the trails as well as cabins, motels and hotels are available.

2860 Baker Highway, Huntsville, Tenn. 423-663-4868, brimstonerecreation.com.