NEW YORK — It is almost enough to gaze mesmerized at the exterior of New York’s iconic Solomon R. Guggenheim Museum without actually going in.

So spectacular from the outside is Frank Lloyd Wright’s modernist masterpiece on Manhattan’s Upper East Side – with its spiraled, sloping central ramp and “continuous spaces” – that whatever may be on display inside might seem an afterthought.

Except, of course, it is not.

“The Guggenheim,” as everyone calls it, is much more than Wright showing off his spectacular genius in creating his seven-level structure often compared to a nautilus shell. It is also full of wonderful art despite its not-exactly-visitor-friendly interior layout.

It’s difficult to fathom that Wright was first approached to design the museum in 1943, and that it was not finished until 1959, 16 years later, at Fifth Avenue and 89th Street.

Still, for a structure that, at almost 55, is middle-aged, it has worn its years remarkably well, looking as if it could have been erected yesterday.

Ultimately, of course, it is what is inside that counts, and a visit earlier this year confirmed that there is certainly enough to behold to leave one inspired and wanting more.

On this visit, for example, there was wonderful thematic exposition of the installation works of James Turrell exploring the “perception and materiality” of light.

Personally speaking, of course, I would much more be inclined to take in a Tissot over a Turrell, but the latter’s use of light to project the “optical and emotional effects of luminosity” was extremely striking and, simply put, unique, as in “I could never think of doing that.” In other words, even if his art does not strike your fancy, Turrell is an obvious creative genius.

The Guggenheim’s permanent collection, by contrast, is more conventional but no less striking.

On Level 2, for example, the Thannhauser Gallery houses some of the greatest art of the French impressionist and post-impressionist periods, including works by Cézanne, Gauguin, Manet, Monet, Picasso, Pissarro, Renoir, and Van Gogh.

What more need one say?

The choice is very varied: Recent and ongoing exhibits include a large exhibit of the works of “post-conceptual” artist Christopher Wool. Until mid-April, check out the exhibition of works drawn by Vasily Kandinsky while he lived in Paris during the 1930s and 1940s. The colours abound and soar.

Or, a Guggenheim “lab” examining urban trends in New York, Mumbai, and Berlin. Or, the early collages of painter and print-maker Robert Motherwell. Or, a tribute to some of Wright’s first structures in New York.

In a way, that’s the whole point about the Guggenheim: a visitor can both be a lover of Cézanne but still receptive to what is different and abstract and bold and even subversive. It’s all part of the fun and the experience.

The museum is also exceedingly ready to help the visitor in any way it can: there are guides walking around with buttons on, as well as public and private tours, organized family, children’s, and adult activities and programs, screenings, help for the disabled, and even a free, downloadable Guggenheim app.

More information on the Guggenheim is available at 212-423-3587 or by visiting guggenheim.org.