Constructed sometime in the mid to late 18th century by a supposedly exiled French nobleman, the eclectic building included a large square tower and turret on a large plot of land. Though considered for landmarking in 1966, just one year after the passage of the Landmarks Law, it was denied and was demolished the same year. It was replaced by the Con Ed "Big Alice" power plant.

Belvedere Castle is one of Central Park's five visitor centers. Calvert Vaux, co-designer of the Park, created the miniature castle in 1869 as a whimsical structure looking out on the reservoir to the north (now the Great Lawn) and the Ramble to the south. Belvedere provides the highest and best views of the Park and the adjacent cityscape. The castle's name is fitting, because it translates to "beautiful view" in Italian. After decades of deterioration, Central Park Conservancy renovated and reopened the castle in 1983 as a visitor center and gift shop.

The Libbey Castle was built in 1856 by merchant Augustus C. Richards (the property was named for a later owner) in present-day Fort Tryon Park. A 1930 history of Fort Tryon properties published in the New York Times referred to Richards's castle as "the most pretentious structure in the section at that time." The castle and the surrounding properties had several 19th-century owners — including the infamous William "Boss" Tweed — before it passed to William Libbey in 1880 via the widow of a business partner, the department store magnate A.T. Stewart.

In 1905, Charles Paterno, a successful real estate developer, purchased a 7.5 acre plot in what is called Hudson Heights today, overlooking the Hudson River. He hired John C. Watson to build him, well, a castle. By 1909 the German style castle was ready for occupants, though it was not fully completed. Residents and visitors of the castle were required to enter through an underground tunnel that ran under the front of the home into a subbasement. Though the overall style of the castle exterior was medieval, in the interior, each room reflected a different period or style. The building was not the only over-the-top feature. The roof garden included an aviary, solarium, and large conservatory. The grounds also had an Italian garden with colonnades, pergolas, and fountains.

Built for Edwin Forrest, the tragedian, by Thomas L. Smith in 1849, this house has both Norman and Gothic elements. Inspired by Foothill Abbey in England, loopholes and buttresses give the structure the appearance of a fortified castle. The highest of its gray granite octagonal towers rises to 70 feet. It now serves as the library of the College of Mount St. Vincent.

Bliss Castle was built by Eliphalet William Bliss, a wealthy industrialist who lived in Bay Ridge in the mid 19th Century. He bought the 26 acres of land that Bliss Castle stood on in 1866 from a former Mayor of Brooklyn. He renovated an existing mansion but added a number of architectural features including the observatory tower (which was called Bliss Castle.) Upon his death, he willed his estate to the city and it is now known as Owl's Head Park.

The Cloisters were the labor of love of American Artist and Art Dealer George Gray Barnard. Having lived in France, Barnard visited many cloisters and bought four cloisters: the Cuxa, Saint-Guilhem, Bonnefont, and Trie, along with a great collection of Medieval works. Unfortunately for Barnard, but for fortunately for us, he sold his collection to John D. Rockefeller during a personal financial crisis. Rockefeller then funded the landscaping of Fort Tryon Park and the building of the Cloisters for the Metropolitan Museum of Art. The cloisters were dissembled stone by stone in France and reassembled at the top of Manhattan.

This stucco mansion, located just inside the entrance at Prospect Park West and 5th Street, was built for Edwin C. Litchfield between 1855 and 1857. A prominent Brooklyn real estate developer and landowner in present-day Park Slope, Litchfield was responsible for the expansion of the Gowanus Canal from a tidal creek into a shipping channel. In 1855, Litchfield hired acclaimed architect Alexander Jackson Davis to construct an Italianate estate for his family. In addition to the hilltop mansion, Davis also built a coach house, greenhouse, and chicken house (none of which remain today). When completed in 1857, the structure was named Grace Hill, after Edwin's wife Grace Hill Hubbard Litchfield.