The former headquarters of the Cunard Steamship Company at 25 Broadway are as grand as that company—responsible for the Queen Mary and the doomed Lusitania, among other ships—was during its heyday. Its enormous Great Hall, as Untapped Cities notes, is covered in intricate designs that “focused on marine and shipping themes for the building.” The first floor, where customers bought tickets for Cunard trips, is so stunning that it was designated an interior landmark in 1995.

The Art Deco gem One Wall Street was designed by Ralph Walker and originally completed in 1931; it’s best known for its glorious interiors, including the Red Room (pictured) and a 49th-floor Observation Room. As part of its conversion from a commercial building into residences and ground-floor retail, the gorgeous Red Room will remain as it is. Hildreth Meière, a muralist who also worked on St. Bartholomew’s Church and Radio City Music Hall, created the space’s gorgeous tile mosaic walls and ceiling, done primarily in scarlet but with lovely gold accents.

What was once the eerie, abandoned Temple Court is now home to the Beekman Hotel, a luxury lodging that’s now open to the public. The circa-1884 building is best known for its nine-story atrium, topped with a gorgeous skylight. Its ornate iron railings and lovely flooring were all restored as part of its transformation into a hotel; now, anyone can wander in off the street and look up at the stunning space (which we highly recommend you do).

Three disparate buildings have been knit together to create this unheralded Midtown gem, but the best interiors can be found in the stately McKim, Mead, & White-designed structure at the south end of the complex. There, you’ll find J.P. Morgan’s exquisite library—essentially the Platonic ideal of such a room—along with the splendid, marble-covered rotunda, a red-paneled study, and other glorious rooms.

There are many beautiful spaces within the New York Public Library’s majestic Fifth Avenue building, but perhaps the most spectacular is the Rose Main Reading Room. After a years-long renovation that spiffed up the enormous research room—which is about as long as two city blocks—its plater rosettes, celestial mural, and ornate chandeliers are all looking better than ever. (The room itself is not landmarked, but preservationists and some local officials are hoping to change that.)

The United Nations complex is full of gorgeous rooms, including the lobby of the Secretariat Building, designed by architects Le Corbusier and Oscar Niemeyer, and the stunning General Assembly, which was recently renovated. One unheralded gem is the Edgar J. Kaufmann Conference Center, designed by Finnish greats Alvar and Elissa Aalto; the room’s soaring ceilings, and stately birchwood sculpture, are simply lovely. They’re also, alas, currently unprotected from destruction, and their fate is currently up in the air.

There are so many beautiful spaces within Grand Central Terminal that you could spend an entire day gawking at them all, from the hidden Campbell Apartment (now a bar known as the Campbell) to the Guastavino-tile-covered Whispering Gallery near the Grand Central Oyster Bar. But the most iconic is undoubtedly the main concourse, with its soaring azure blue ceiling painted with a celestial scene. Even the most jaded New Yorker can’t help but be wowed by the stunning space.

One of New York’s many Art Deco stunners, Radio City Music Hall is full of gorgeous interior spaces. The soaring lobby, covered in a mural by Ezra Winter, is just the beginning; everything from the theater itself, with its simple-but-beautiful design, to the downright luxurious bathrooms, feels as beautiful as it must have when the theater opened in the 1930s. (A restoration helmed by Hugh Hardy certainly helped.)

Thank the 1964 World’s Fair for this untouchable midcentury gem: Built as part of the state’s cultural participation in the fair, the David H. Koch Theater (the New York State Theater until the oil billionaire donated $100 million in 2008) was designed by midcentury master Philip Johnson and John Burgee. The AIA Guide to New York City describes the building as the “most frankly Classical building facing the [Lincoln Center] plaza,” citing its “under-stated Baroque” lobby and ornate foyer with “tiers of busy railings,golden chain drapery, and a velvet ceiling, all dominated by two superb white marble sculptures.”

The city’s only bookstore devoted to French titles is as striking as you’d expect, especially considering its location: it sits on the first and second floors of the French Embassy on Fifth Avenue, which itself is located in Stanford White’s stunning Payne Whitney House. The bookshop is a beautiful place to wile away an afternoon, not least because of its ceiling, a stunning hand-painted mural that was “modeled after the extraordinary ceiling of the music room at the Villa Stuck in Munich, Germany,” per the shop.

The Guggenheim Museum on the Upper East Side is one of the most famous—and most photographed—buildings in the world. The Frank Lloyd Wright-designed structure has been an object of fascination for shutterbugs since it opened 60 years ago, thanks to its unusual shape, which has been compared to a nautilus shell and a concrete ribbon.

Thank Stanford White for this glorious structure, which the architect designed to mimic Rome’s Pantheon. Its best-known interior space is the rotunda, which is topped with an enormous dome; marble columns and stained-glass windows are other decorative elements. And per a Times article on the space (which is in need of a restoration), both the Bible and Paradise Lost are quoted, appropriately, on various parts of the structure.

Architect Wallace Harrison is responsible for this imposing concrete structure, whose shimmering interior is one of New York’s greatest surprises. The Great Hall, as it’s known, was created using a technique called dalle de verre, in which thousands of bits of blue glass were embedded into the concrete, creating an eerie, lost-in-space effect. (That’s no accident, obviously; the building opened during the future-obsessed 1964 World’s Fair.) The hall recently received a renovation courtesy Ennead Architects that spiffed up the space without taking out its original character.

Despite years of disuse, Eero Saarinen’s TWA Flight Center at JFK Airport is still a pristine, space-age marvel. Its gorgeous curved structure—innovative at the time, and still fresh to this day—is the opposite of what one expects from an airport experience, made all the more interesting thanks to the pops of color throughout. Stepping into it is like entering a time capsule back to the golden age of air travel—and with any luck, that feeling will be preserved when it’s incorporated into a boutique hotel in the coming years.

One of Brooklyn’s most majestic theaters wasn’t always that way. King’s originally opened in 1929 as one of several Loew’s Wonder Theaters; but by the 1970s, it was underutilized, and was eventually left to rot for nearly four decades. But thanks to a painstaking restoration, completed in 2015, the theater is back and better than ever. Its opulent decorative details were re-created (down to the paint colors), and it’s now one of Brooklyn’s most beautiful music venues.