Not only is it the nation's oldest continuously operating distillery, in business since 1787 and chock full of cool old buildings, but Buffalo Trace is the rare distillery with free tours and tastings. The hour-long standard tour leaves every hour on the hour (more frequently if needed); last one is at 4pm (3pm Sunday). A tasting-only option is available every half hour.
No reservations are needed for the standard tours, but bookings are required for special tours such as the evening ghost tour (7pm Thursday to Saturday).
Note to bourbon buffs hoping to get a sample or bottle of Pappy Van Winkle (Buffalo Trace's revered, rare brand): it's not available on-site.
Weirdly, Buffalo Trace isn't on the official Bourbon Trail, so you won't find it listed on the trail map and passport. Despite this, it remains one of the area's most popular sights.