Lynnewood Hall (920 Spring Ave, Elkins Park, PA) is 70,000 square feet and has 110 rooms on 34 acres.
Located about 30mins north of Philly, the mansion was built in 1900 for industrialist Peter Widener. His son and grandson died when the Titanic sank in 1912. Then Peter died in 1915.
The mansion went through a variety of owners until being abandoned in 1952.
Currently, the property is on the market for $11 million dollars.