A cave right inside Bowling Green city limits, Lost River Cave is an unusual attraction: you board flat-bottomed boats and float through a cave on an underground river, guided by rangers who point out rock formations and the cave's layered history. The cave was used as a speakeasy during Prohibition and still has the remnants of the old nightclub stage.
The cave system is short — boat tours last about 45 minutes — but worthwhile, especially on hot summer days when the cave air holds at a steady 57°F (14°C). Above ground, the property has a butterfly garden, zip line, and walking trails through the woods. It's a good half-day outing and an interesting counterpoint to Mammoth Cave: smaller, quirkier, and far less crowded.