Graz, Austria, is known as the City of Design (according to UNESCO), the City of Culinary Delights (say the foodies) and the Green Heart of Austria (proclaim the locals).

It’s the second-largest city in German-speaking Austria, a distant 275,000 souls to Vienna’s 1.8 million.

And now its secret is out.

While tourists flock to the Habsburgs’ stately Vienna and Salzburg’s Sound of Music, Graz lies under the radar (likely not for long).

This quasi-Mediterranean city offers a whiff of Italy: Italianate Baroque curls inhabit its many ornate edifices. And a sense of vivace fills the city’s open-air market, though it’s pumpkin seed oil, not olive oil, that the vendors here sell.

I stayed at Hotel zum Dom in Old Town: “Oh, it’s famous!” my taxi driver said with an air of respect. (It’s just a missal’s throw from the “Dom” itself, the Cathedral of 1438.)

In my room at the former palace, also known as Palais Inzaghi, I found a crimson velvet settee and a four-poster bed — with plush drapes to match.

In the hotel’s sunny breakfast room, there was a deli spread to rival that of Dean & Deluca, along with all the cappuccino I could swallow.

I started my tour with a visit to the Dom, famed for a fresco titled The Plagues of God. Beware, or He’ll send locusts. And Turks.

Next I visited Stadtpfarrkirche, another place of worship just a few block away, circa 1439, featuring a glorious Tintoretto altarpiece. Here an equally brilliant modern stained glass window depicts Christ, mocked by unbelievers, including Hitler and Mussolini.

Here and there around town, you might spy the tag of a past Habsburg-era Emperor, A-E-I-O-U, bragging (according to some interpretations) “Austria Est. Imperator of the Universe.”

Graz, Austria, offers one-of-a-kind attractions (modern and historic), plus a rich culture packed with culinary delights

Climb Castle Hill

Today the city’s central fortress is gone, destroyed by Napoleonic forces.

What remains is Schlossberg — a forested mountain that rises over the medieval town center, crisscrossed with walks from all sides.

You can ascend to this city pinnacle via countless (I stopped after 200) steps, built by Russian POWs, for a spectacular view of the red-tiled roofs below — or you can ascend via elevator within the mountain’s tunnel-turned-performance space.

Crowning the city’s so-called Castle Hill is actually a clock tower. (Napoleon was paid a ransom to spare the town’s beloved symbol.)

Peering down, across the tumbling river, you’ll spot what appears to be a beached blue glass whale. It’s actually the beloved Friendly Alien, as townsfolk call their modern-art museum of 2003.

Behind it, a once-dodgy neighborhood now harbors hipster shops, offering gotta-have jewelry, designer specs, artisan pottery and handbags of recycled webbing.

If you cross the river’s pedestrian bridge, which slices through a man-made mini-island (known as Murinsel) sporting a trendy café, you’ll find stylish Sackstrasse, an avenue anchored by K&O, Austria’s largest department store.

Ride the escalator to Floor 6 to find an open-air café for a selfie overlooking those terraco a rooftops. Back on the street, you’ll find the city’s most-visited attraction, the Landeszeughaus Armory (OK, it’s a guy thing), showcasing four floors of old-time weapons, including swords, lances, muskets, pistols and helmets.

Nearby, a museum of city history explains how Graz is different from rivals Salzburg and Vienna. Farther afield, the Joanneum Quarter features a cache of underground collections below a concrete plaza.

I favored the Neue museum with its arresting meander through Austria’s recent art history, from Impressionism to Realism and the postwar Avant Garde.

Let’s eat!

Interested in those Culinary Delights?

A grand place to start is Glockenspiel Square. First direct your eyes to the clock tower where, three times daily, a door opens and a figure of a farmer in lederhosen, hoisting a stein, dances around a dirndled lass, forever waving her hankie.

After a click of the camera, aim for the door of Glockenbrau below, a brewery-turned-eatery celebrating the state of Styria’s comfort food like krausflerl (cabbage and bacon tossed with pasta snippets) and its famed breaded-chicken salad, delivered by a weight-lifting champ with four arm-long steins of beer in one fist, two platters in the other.

By the time everybody clinks a “Prost!” it will be time for another round.

Cozy Altsteirische Schmankerlstube, near the armory, has been in business forever, enticing regulars with creamy garlic soup, roast pork with kraut and dumplings, wiener schnitzel — and, for dessert, a pumpkin seed ice parfait.

Eckstein, near my hotel, offers modern takes on grandma’s classics, such as duck reimagined with oyster mushrooms, okra and smoked peppers; “crunchy leg” of suckling pig; and cabbage, spritzed with port wine and champagne.

See the countryside

To get to the source of all this local bounty, head to the Green Heart of Austria — the Thermenland countryside, emerald with forests, orchards and lilac blooms, past maypoles trailing silky ribbons.

At The Zotter chocolate factory, you can indulge your Inner Charlie on a multi-taste tour, sampling by countries of origin, percent of cacao and degrees of roasting at more than 100 stations, including a hot chocolate bar.

Then head on to Castle Riegersburg, perched on a volcanic mountaintop — a never-conquered 12th-century fortress whose moat, today, is filled with grazing pigs.

It houses three museums — one on weaponry; another featuring the ornate medieval rooms of its wealthy owner; and finally, an expo of 16th-century witches.

Our escapade ended at Weingut Krispel, where we sipped the winery’s fruity Rieslings and crisp Sauv Blancs at its May Day party, seduced by oompah bands and mountains of homey eats.

Meet you there this May Day? Check out visitgraz.com to make it come true.

Carla Waldemar is an award-winning food/travel/arts writer who lives in Uptown.