The colonnade row of La Grange Terrace was built in 1833 by architects Alexander Jackson Davis and Seth Geer. The nine row houses (of which four still exist) were commissioned by John Jacob Astor. They buildings are also listed on the National Register of Historic Places. [Photo via Jim.Hendersen]

The William and Rosamund Clark House may not appear special, but the 1825-built home is an early example of Federal style in the Lower East Side, and was built when the neighborhood was an affluent residential area. The house was reportedly commissioned by grocer William Clark. [Photo via AmericasRoof]

Astor Library, also known as the Hebrew Immigrant Aid Society Building and nowadays as Joe's Pub, was built from 1849 through 1881 by Alexander Saeltzer, Griffin Thomas, and Thomas Stent in the Rundbogenstil and Victorian styles. The building was initially intended to function as a research library with a non-circulating catalogue, but ended up consolidating with existing organizations to form the New York Public Library. [Photo via NYC-Architecture].

Arguably the centerpiece of the Staten Island maritime complex originally built for aging sailors, the Sailors' Snug Harbor dormitories on Richmond Terrace were constructed from 1833 to 1880 by Minard Lafever and Richard P. Smyth in the Greek Revival style. The Sailors' Snug Harbor campus is a National Historic Landmark as well as on the National Register of Historic Places. [Photo via Dmadeo]

The veteran memorial chapel on the maritime campus was built in 1854 in the Italianate style by James Solomon. The renovated chapel now serves as a recital and concert space. [Photo via Jim.henerson]

Battery Park's Castle Clinton, whose endearing tag line from the National Park Service is "Built to keep people out; now welcomes millions in," was built in 1812 to thwart a British invasion. McKim, Mead & White worked on the project as well as John McComb and Jonathon Williams. [Photo via NPS]

This gorgeous cast-iron building was constructed by J.P. Gaynor in 1856 to serve as Eder V. Haughwout's Fashionable Emporium, which sold imported cut glass, silverware, hand-painted china, and chandeliers to the likes of Mary Todd Lincoln. The building was home to the world's first successful passenger elevator. Haughwout's is also on the National Register of Historic Places. [Photo via Beyond My Ken]

This full-block neo-Renaissance building was constructed from 1919-1924 and serves as the home of the Federal Reserve Bank of New York. The building was designed by McKim, Mead & White protégés York and Sawyer. [Photo via Beyond My Ken]

Referred to by the National Park Service as the "Birthplace of American Government", the Greek-Doric-style Federal Hall was constructed in 1842 and was in essence where George Washington was sworn in (a different iteration; Washington was inaugurated in 1789), and also served as home to the first Congress, Supreme Court, and Executive Branch offices. [Photo via NPS]

Although it's now a museum, Fraunces Tavern was constructed in 1719 for use as a bar, and ended up becoming the first offices for Foreign Affairs, War and Treasury following the Revolutionary War. The building has also operated as a boarding house, historic gathering place, and a restaurant. [Photo via Fraunces Tavern Museum]

Now used as the Brotherhood Synagogue, the two-story building at 144 East 20th Street on Gramercy Park was constructed in 1859 as the Friends Meeting House. It's built in the Anglo-Italianate style and is made almost entirely of Dorchester olive stone. It became a landmark on October 26, 1965. [Photo via PropertyShark]

Last year, the India House celebrated its 100th birthday in its home at 1 Hanover Street, but the landmarked building existed for decades before the private club moved in. Built by Richard F. Carman in 1853, the Anglo-Italianate style brownstone building was the headquarters of the Hanover Bank, and in 1870, the New York Cotton Exchange was born here. [Photo via Wikimedia Commons]

Built as the home for J.P. Morgan and his family, the mansion at 231 Madison Avenue became a public institution in 1924, in accordance with Morgan's will. Today it's known as the Morgan Library & Museum. The building is unique because it's exposed on three sides, displaying many of its architectural details, including a stone balustrade with Doric balusters, a porch with Corinthian columns, and wrought iron balconies. It became a landmark on November 23, 1965. [Photo via Property Shark]

The James Watson House, now the rectory of the Shrine of St. Elizabeth Ann Bayley Seton, is a more unusual building, as it curves to follow the shape of State Street. It dates to 1793, and it is the last reminder of the Federal-style townhouses that once lined the street. In its November 1965 designation report, the LPC said its state of preservation was "a near miracle," as the owner "spared no pains or expense to maintain the building." [Photo via Wikimedia Commons]

The John Street Church was built in the Georgian style in 1841, with attribution for its design given to Philip Enbury. The church was also listed on the National Register of Historic Places in 1974. [Photo via Beyond My Ken]

Commissioned by Leonard Jerome in 1859, 32 East 26th Street was intended to be the "largest and most opulent" home of its time. After Jerome and family moved out, the building played home to several high-society clubs, including the Manhattan Club. Despite its landmarked status, the building was bulldozed in 1967, and now in its place stands the 42-story Merchandise Mart skyscraper. [Photo via Daytonian in Manhattan]

Another landmark that fell to the wrecking ball is the New Brighton Village Hall that was built between 1868 and 1871 in the Second Empire style. The James Whitford-designed building was torn down in 2004 because of neglect. [Photo via Forgotten NY]

This 19th-century house became a very lovely museum in 1936, and claims to be the only home in the city preserved as-is from that era, both inside and out. Also called the Seabury Tredwell House, it was built on spec by a milliner, who then sold it to Seabury Tredwell, an affluent merchant who lived there with his eight children and an array of servants. Their original possessions remain inside to this day. A recent preservation battle brewed when developers tried to build a tall-ish hotel next to the architecturally fragile structure. [Photo via Wikipedia]

The old Bronx Borough Hall was located on top of a rocky plateau at the southeast intersection of Tremont and Third avenues. The pictuaresque three-story building was designed in the Renaissance style. It was consumed by a massive fire in 1968, after which it was deemed structurally unsafe and torn down. [Image via Our Old Neighborhood]

A rare example of the Art Nouveau architectural style in New York City, this pretty building is the former home of the New York Evening Post that also housed its printing plant. It dates back to 1906, back when the area around City Hall Park was still dotted with publishing enterprises. The building's mansard roof has four sculptures, all related to the trade. Yes, it's a landmark, and such a valued one that the Landmarks Preservation Commission itself had offices here between 1980 and 1987. [Photo via Flickr/epicharmus]

The quaint 1804-built Federal-style home was the birthplace and childhood dwelling of New York State Senator and Governor Hamilton Fish. The building is now owned by Cooper Union and used as lodging for the university's president. [Photo via Wikimedia Commons]

Architectural historian Christopher Gray called the Brooklyn Navy Yard a "muscular collection of industrial architecture," describing one of the city's earliest landmarks as such: "the magnificent, slightly sagging Naval Hospital, a ghostly marble temple built in 1838 and empty for two decades." It's been bait for abandoned-building lovers for just about that long, and has been named an endangered building by the Landmarks Conservancy. The rest of the massive navy yard complex is undergoing major repurposing and renovation, so will the hospital come next? [Photo via Atlas Obscura]

A pristine example of early Greek Revival architecture in Lower Manhattan, congregants have flocked to this site for prayer even before the house of worship that we know today was completed in 1834. It's the oldest Roman Catholic parish in the U.S.; during 9/11 it morphed into a staging area for emergency responders. [Photo via Daytonian in Manhattan]

As per historian James Nevius, who chronicled the 20 oldest buildings in NYC for Curbed, "In 1652, the Flatlands section of Brooklyn was centered around the Dutch village of New Amersfoort. That year, Pieter Claesen Wyckoff—a former indentured servant from Rensselaerswyck near Albany—and his wife Grietje, moved to Brooklyn and likely built this one-room farmhouse where they raised their 11 children. After many years of additions, that original room is the kitchen of the house-museum, and it gives remarkable insight into the lives of Dutch farmers on what was then frontier." [Photo via James Nevius]