Waveland State Historic Site preserves an antebellum house, outbuildings, and grounds tied to Lexington's plantation-era history. It is a useful counterpoint to the city's horse-country image because it puts domestic life, agriculture, and slavery into the same landscape.
Guided tours are the reason to go; the house makes much less sense as a quick exterior stop. Combine it with other south-Lexington sights or allow extra time if the seasonal gardens are looking good.