The Metropolitan, Guggenheim, and Museum of Modern Art are galleries that have become iconic of New York City. However, New York has a lot more to offer, and these hidden museums and galleries show the pure grit and amazing underworld of New York City culture.

1. The Met Cloisters

The lesser-known outpost of the Met, the Cloisters is an art museum housed in a medieval folly recreation of a European monastery. It features some of the best architecture in the city with its 1930s frescoed arches and columns. According to NZ Herald, some of these features were salvaged from abandoned European abbeys and built with a medieval style garden overlooking the Hudson River and Fort Tryon Park.

2. Lower East Side Tenement Museum

During the extravagance of the Gilded age in the early 1900s, this museum tells the other side of that story, focusing on the life and work of New York City's working class immigrants. The five-story tenement building housed about 7,000 people then, and was falling into disrepair, that the tenants were all evicted.

The building was sealed off till 1988 and remained undisturbed, creating a time capsule of the era. Today, it acts as a museum and has been curated so that tourists can come into the rooms and experience the stories and struggles of its inhabitants.

3. Skyscraper Museum

With New York City hosting some of the world's most popular skyscrapers like the Woolworth Building and One World Trade Center, this museum has been devoted to following the life and times of these buildings. Designed by Skidmore, Owings and Merrill, who are responsible for a lot of New York City's skyscrapers, the museum includes photos of the ever-changing skyline and a permanent installation model of the historic Twin Towers.

4. City Reliquary Museum

According to Conde Nast Traveler, this ubiquitous gallery is disguised as a tiny storefront and is sandwiched between a bar and a pizza joint in Williamsburg. This museum features quotidian knickknacs from New York's quirky, slightly seedy past. Some interesting things you can find here are old seltzer bottles, postcards, and even a locker filled with burlesque costumes and accessories.

5. The Morgan Library

Owned by famous financier J.P. Morgan, the illustrious pink marble building was even given the starchitect treatment with Renzo Piano adding a sleek, modern entrance in 2006. Gold-gilded rooms and frescoed ceilings in the large library house a vast assortment of books, manuscripts and letters. Priceless art from artists such as Rembrandt and William Blake hang on the walls, while some panels and bookshelves actually act as secret passageways to different rooms.