This is one of the finest of the Hudson Valley mansions, as its owner, celebrated landscape painter Frederic Church, designed every detail, inspired by his travels in the Middle East and his appreciation of the beautiful views across the Hudson to the Catskills. The 'Persian fantasy' house is extraordinary and it's well worth booking ahead for a tour of the interior, where you can also see many of Church's paintings.
There are also guided walking and driving tours of the grounds (which you're free to explore in your own car as well). Olana underwent a major rejuvenation which was completed in 2018.