Fresh tamales are just one of the sumptuous staples of Mexico City's vibrant street food culture, which we explore on our Street Food Paradise walk.

Between two simple slices of bread exists a mind-boggling array of possibilities – something not lost on Spaniards, who have turned sandwich making into something of an art form. In Spain, sandwiches go by different names depending on the kind of bread used and local custom. The type that’s generally called a bocadillo in Spanish and entrepà in Catalan traditionally comes on pan de barra, itself a broad category of bread, with varying dimensions, qualities and more specific names, including baguette, maybe chapata (ciabatta), depending on how round the bakery makes it, pistola (pistol) in Madrid and flautas (flutes) in Barcelona if it’s short and very thin.

Barcelona’s food shops and colmados offer culinary treasures all year long, but the holidays are a particularly exciting time for browsing their wares. The festive window displays show magnificent gift baskets overflowing with tasty treats – with many Spanish and Catalan specialties among them. Perhaps the most desirable items in holiday gift baskets here are the seasonal sweets, which previous generations would amass in quantities that would serve as “emergency” treats for unexpected guests the rest of the new year. (Thankfully, one can now find these year-round, so there’s no need to hoard them.) We’ve written previously about artisanal turrón, which continues to be handmade by a few family-run companies.

Some of the best tacos in Mexico City are found on the street, and they are among the delicacies sampled on our Mexico City, Street Food Paradise walk.

All around Messinia lie endless fields of olive trees, their silvery leaves shining everywhere you look. This region in the southwestern part of the Peloponnese has been known for its fertile land since ancient times. Some of the best olive oil in the world comes from here. The capital, largest city and central port of Messinia is Kalamata, known around the globe, of course, for its famous namesake olives. It lies at the top of the Messinian Gulf, with a view of the water’s blue expanse. Above it towers the imposing Mount Taygetos. Together, the mountains, sea and land have created a gastronomic paradise.

As one approaches the port of Ermoupolis (named after Hermes, the god of commerce), the main town of the island of Syros and capital of the Cyclades, one cannot help but marvel at its beauty and grandeur. Imposing public buildings and private mansions, marble-paved streets, a large Italian-style piazza and numerous churches make the city one of the best preserved examples of 19th-century architecture in Greece. This should not come as a surprise: in the aftermath of the 1821 Greek War of Independence from the Ottoman Empire, Syros developed into an important commercial, cultural and industrial center, as refugees from Asia Minor, Chios, Crete and other areas found a safe haven from the war on the small island.

Thessaloniki, the capital of Greek Macedonia and the country’s second largest metropolis after Athens, 500 km to the south, is a youth-loving, vibrant city that never sleeps – and always eats. Most locals here are friendly, laid-back, natural-born foodies who love going out and enjoying good wine and tsipouro. It’s a city with a very long history of culinary hospitality. Founded by King Cassandros in 315 BC and named after Thessalonike, his wife – half-sister of Alexander The Great – it’s referred to by Greeks as symprotevousa, “co-capital,” because of its historical status as a co-reigning city of the Byzantine Empire, along with Constantinople. In 1492 the city welcomed a large number of Jews expelled from the Iberian Peninsula.

There’s an old Catalan saying that goes, A Vic, llonganisses, frares i misses (“In Vic, cured sausages, friars and masses”). The capital of the Osona region – equidistant between Barcelona and the Pyrenees – was indeed for a long time an important religious town: it is said to be one of the towns with the highest number of convents and churches in Catalonia. Nowadays, university students and a diverse off-campus population have largely replaced priests and nuns, while masses have been swapped for music, film and other cultural festivals. Cured sausages, though, have managed to retain their place in local culture and are in evidence in every single pork deli shop window in this central Catalonia town.

Our “Culinary Secrets of the Old City” walk goes beyond the major monuments and into the backstreets where all of the serious eating is done. We’ll set off through the atmospheric, lesser-explored market streets around the Egyptian Spice Market and then go deeper into the untouristed Fatih neighborhood.

Editor’s note: We’re celebrating another year of excellent backstreets eating by taking a look back at our favorite restaurants and dishes of 2015. La Panxa del Bisbe Xavi Codina has created a menu of almost 30 tapas or platillos (small dishes) and four desserts, combining traditional Catalan cuisine with international influences that Codina has encountered in his life or in the neighborhood. Much of the menu changes according to season and customers’ tastes, but there are a few perennial favorites, such as the homey croquettes, with their generous quantity of chicken and carrots; duck liver with pears and wine; and the cap i pota, a traditional dish made from pork trotters and head, which the chef tweaks throughout the year.

The subject of frequent arguments over who actually invented it, baklava has a history as multilayered as the flaky dessert itself. The story may actually go all the way back to the 8th century BCE and the Assyrians, who layered bread dough with chopped nuts and honey and baked the result – a kind of proto-baklava – in wood-burning ovens. Perhaps carried by the winds of trade, different versions of this ancient dessert appeared on Greece’s shores a few centuries later. The 3rd-century-CE Deipnosophistae ("Banquet of the Learned") – sometimes referred to as the oldest surviving cookbook – provides the recipe for gastrin, aka Cretan “Glutton Cake,” a sweet that also seems to presage the arrival of baklava as we know it. The instructions, attributed to Chrysippus of Tyana, one of the leading dessert experts of antiquity, calls for turning various chopped nuts, boiled honey and poppy and sesame seeds into a paste which is then spread between two sheets of thin, rectangular dough. At a certain point, ancient Greek cooks started using thinner sheets of pastry, better known as phyllo – Greek for “leaf” – getting closer to today’s baklava.

Some islands, Mykonos and Santorini for example, are known for their temples of gastronomy. Others, like Tinos, Milos, Syros and Sifnos, possess solid reputations for uniformly excellent tavernas. Until recently, Andros, a green anomaly in the treeless, windswept Cycladic chain, had two main attractions for tourists: a world-class modern art museum and a network of well-maintained hiking trails. You could get a decent meal after you’d seen the exhibition in Hora or trekked up to a 1,000-year-old monastery or down a river lined with water mills, but it wouldn’t be something to write home or tweet about.

On recent visits to Madrid, we’ve noticed that a new breed of food market has taken hold of the city’s attention. While the traditional kind with food stalls slowly disappears, vibrant, culture-focused gastromarkets are booming. In addition to great food, they offer a mix of businesses, along with cooking demos, live music, exhibitions – the list goes on. In 2009, the private society El Gastródomo de San Miguel refurbished a beautiful building that was built in 1916 and located very close to Plaza Mayor. It was opened as the “culinary space” Mercado de San Miguel. Though the initial inspiration was Barcelona’s La Boquería, San Miguel is utterly different, with its own colorful, unique personality. The market is dedicated not just to selling quality seasonal foods, but also to allowing visitors to enjoy them in situ, at tables and chairs distributed throughout common areas. They can choose from cod, fresh shellfish and other seafood, various vermuts, pickles and olives, paella, churros, Spanish wines, international beers, delicious Iberian ham and cured sausages and cheeses, ice cream and non-Spanish items, such as pasta or sushi. Unsurprisingly, the concept has been a hit, and other similarly styled markets have since popped up around the city.

When we think of white wine in Catalonia, we think of its seemingly endless possibilities. Production of whites here has a 2,000-year-old history. The wide-ranging diversity in the area’s Mediterranean climate and calcareous soils, from the mountains to the sea, and the combination of old grape varieties and newly introduced “foreigners” with traditional and experimental methods of production make for innumerable styles and no taboos. Who knew white was a color with so many variations? The traditional Catalan grape varieties used to make white wine are mainly macabeo, xarel-lo, parellada and garnatxa blanca, but this area of Spain has the largest number of white grapes included in all its protected appellations (D.O.). Where other Spanish D.O.s usually are deeply defined by one or a few varieties, in the Catalunya D.O. there are more than 16 allowed – 35 counting the reds. In fact, this umbrella appellation, which covers wines that do not fall under the 10 subregion designations (Montsant, Penedès, etc.), was created to allow the use of all the grapes of the other Catalan designations in the entire area. It implicitly gives freedom to Catalan winemakers to express more than the old narrower conceptions of terroir and opens the doors to experimentation.

Dear Culinary Backstreets, I’ve noticed that a dish called “moustalevria” pops up in shops all over Athens in the autumn months. What is it, and where can I get it?