While in Newport, Rhode Island (another fun east coast city to maneuver in an RV), I toured two mansions: Rosecliff (pictured) and Marble House. 

Rosecliff  has a red-carpeted, heart-shaped stairwell that was at one time covered in a foot of ice while the mansion was abandoned and in disrepair.

Marble House was built to be the summer abode for William K. and Alva Vanderbilt and their three kids. The family spent just three summers together in it.

Alva, a notoriously strong-willed feminist, received the mansion as a "gift" for her 39th birthday.

Everything inside was on a large, fairytale scale.

According to Wikipedia, Marble House would have cost about $140 million to build today.

Both homes were used during filming of "The Great Gatsby," released in 1974. No pictures were allowed inside.