Pull over near mile marker 81. Most people driving between Kona and Ka just want a quick restroom break, but Manuka State Park gives you a weird, wonderful shift in climate at 1,700 feet elevation. Cool, misty air. You step out of the hot car and right into a noisy canopy of birds, surrounded by plants that early foresters shoved into the soil back in the 1930s to see what would survive. It worked. Today, native hia trees stand right next to bizarre, towering exotic species from India and Africa, creating a strange botanic experiment along the highway.

If you have two hours, grab your bug spray and hit the two-mile nature trail loop. Watch your footing on the lava. The dirt trail snakes past sharp, jagged a flows and drops you right at the edge of a massive pit crater choked with fern growth. It looks like a giant sinkhole. Actually, the ground dropped down during an ancient volcanic collapse, so standing on the rim offers a creepy peek straight into the islands subterranean skeleton. Pack lunch, though. The open wooden pavilion makes a great, quiet spot to eat before you hit the long highway again.