Abraham Lincoln Birthplace National Historical Park: The cabin enshrined here is from the same time period as the one Abe was born in but isn’t THE cabin he was born in. It’s still a great tribute to the 16th President.
Camp Nelson National Monument: A supply depot, a training facility for African-American troops during the Civil War, and a cemetery.
Mammoth Cave National Park: The longest known cave system in the world, with over 400 miles mapped so far. Also a UNESCO World Heritage Site.