Anthony J. Drexel Biddle was the inspiration for the 1967 Disney film 'The Happiest Millionaire.' He was certainly unusual: He kept alligators as pets; hosted "boxing teas" wherein locals boxers would spar with him before a formal dinner; and trained Marines by ordering them to attempt to kill him. This Greek Revival-style mansion and estate in Bucks County—which can be visited—was used by the Biddle family for more than 200 years. The home is known for French, English, Chinese and American furniture collection as well as a spectacular 19th-century "gentleman's library."

Though Penn actually spent only four years in America, he left his mark. That's partly because of all the land he owned, which was bequeathed to his father by King Charles II. Pennsbury is the only surviving Penn family estate, though they also lived at the Slate Roof House mansion at Second and Walnut. The Georgian manor was recreated in the 1930s by the same architect responsible for Colonial Williamsburg, and the entire site is now faithful to the period.

John Wanamaker, inventor of the money-back guarantee, is best known in Philly for the store that's now called Macy's. His country estate, Lindenhurst, was in Cheltenham on York Road below Washington Lane. In 1907, the original Victorian Lindenhurst burned down (destroying a lot of art), and it was rebuilt in the neoclassic style. In 1929, Henry Breyer (yes, that Breyer) bought the abandoned property and donated it to the Boy Scouts. It was destroyed in 1944.

Stephen Girard, founder of Girard College and bankroller of the War of 1812, was perhaps one of the city's most prolific, most wealthy and most idiosyncratic historical whales. Gentilhommiere, Girard's country estate, was located at what is now 21st and Shunk in the Girard Estates neighborhood. The estate was situated on 500 acres and came with the relatively modest home and a working farm where Girard pursued his agricultural interests. He left the land to the city upon his death but stipulated that it had to generate income for Girard College. Some 481 homes were constructed on the land in a rare planned community within city confines. They were rented until the early 1950s, at which point they were finally sold.

Hope Montgomery Scott was the daughter of investment banker Colonel Robert Leaming Montgomery. Vanity Fair once dubbed her the "unofficial queen of Philadelphia's WASP oligarchy," and she served as the inspiration for Tracy Lord in 'The Philadelphia Story,' played by Katherine Hepburn. Ardrossan, the 750-acre estate in Radnor, was named for the family's hometown in Scotland. The Georgian manor featured 50 rooms, including accommodations for 30 and required 12 full-time staff to manage it. The full estate housed several other structures, one of which was a working farm known for producing an award-winning herd of dairy cows.

Peter Widener invested his public transit fortune to help found U.S. Steel and American Tobacco and invested in Standard Oil. His home was Lynnewood Hall, a neoclassic revival mansion in Elkins Park with 110 rooms. It's the largest surviving Gilded Age mansion in the region, and a source of much passion among preservationists. Rumor has it the interior, like the exterior, has deteriorated significantly. It's currently owned by a church group that won't grant entrance to the public. Widener donated his first mansion (at Broad and Girard) to the Free Library to honor his late wife; later he lost his son and grandson aboard the Titanic.

William Welsh Harrison hired architect Horace Trumbauer when the draftsman was just 23. The relationship proved fruitful. In 1893, Trumbauer built this mansion—now a National Historic Landmark—based on a medieval castle. When Harrison died in 1927, Arcadia College purchased the building; it now houses administrative offices.

Princess Grace of Monaco, the Hollywood star who gave her film career up for Prince Ranier, was born and raised in Philly—East Falls, specifically. Her childhood home on Henry Avenue has been a stop on tours by the East Falls Historical Society and the Society is advocating for a historical marker at the site.