The first time we approached the stand of the legendary fish sandwich man, we were pleasantly surprised by what we saw: a dark, portly man with a glorious mustache (hence Mario, our nickname for him) turning fish on a portable grill cart next to the Karaköy waterfront. He had a long line of people patiently waiting for an hour to get their order in. He is surrounded by other balık ekmekçi trying desperately to ride the wave of his success, but they struggle to survive.

There’s more to downtown D.F. than tourist attractions, however. It is the cultural, political and economic heart of the city and the country. Any item imaginable can be bought downtown. There’s the lighting district as well as one for appliances, clothing, electronics, printing and a long list of others. For generations, people have been going there to buy by the piece or wholesale to supply small businesses all over the country.

Let us begin with a little Greek mythology. Hermes – son of Zeus, god of thieves and commerce and messenger of Olympus – and Krokos, a mortal youth, were best friends. One day, while the two friends were practicing their discus throwing, Hermes accidentally hit Crocus on the head and wounded him fatally. On the very spot where he was felled, a beautiful flower sprang up. Three drops of blood from Krokos’s head fell on the center of the flower, from which three stigmas grew. This is just one of many origin stories for Crocus sativus, or the saffron crocus, whose crimson stigmas are harvested to make the highly prized spice of the same name.

While Americans celebrate Halloween this week with M&Ms and Milk Duds, in Catalonia this time of the year is marked with a different, more sophisticated, kind of sweet. The small, round marzipan cookies called panellets are, along with roasted chestnuts and sweet wine, the traditional fare of All Saints’ Day, or Tots Sants in Catalan.

Shanghai offers a huge range of dining at every price point imaginable. Fortunately for us, cost is not necessarily commensurate with quality in this town; you don’t have to break the bank to eat well. In fact, some of our favorite eateries offer bargain set lunches. Mi Xiang Yuan Hidden down an alley, Mi Xiang Yuan, a Shanghainese joint owned by a local celebrity chef and his family, serves affordable set lunches that bring in the crowds. Try their marinated pork rice bowl (卤肉饭, lǔròu fàn) or "lion’s head meatballs" (蛤蜊牛蒡肉圆套餐, gélí niúbàng ròu yuán tàocān), and you’ll also get a side of soup, tofu and vegetables of the day plus a bowl of rice, all for less than 30 RMB ($5), no matter which benbang main you try. You can’t beat that price in the Xintiandi neighborhood.

Rio’s small traditional bars, known as botequins, are by definition simple establishments, where orders are usually taken down with pen and paper – and sometimes not taken down at all, but mentally noted. But even in these fuss-free eateries, times they are a-changin’.

Farooj al Zaeem is, pretty much, the best kind of restaurant made to resemble the worst kind of restaurant. If the neighborhood – one of Beyoğlu’s most unkempt snatches – doesn’t send you running, then the look of this place, like a knockoff polo shirt with misspellings, will signal that something here is not right.

There’s a light scent but not much taste to the fresh truffle we just picked up from a local Chinese market. On a tea scale it weighs in at 18 grams and is the size of a healthy walnut. This year’s price for fresh truffles from France or Italy is many times more than the roughly US$6.50 price tag for this earth-coated Chinese truffle (松露, sōnglù).

Horn of plenty, yellow foot, ox tongue, gray knight: the bewitching names are like something out of a fairy tale. But at Casa Lucio, in Sant Antoni, these are all mushrooms you might find on your plate, especially in autumn.

Editor's note: We're celebrating Mushroom Week at Culinary Backstreets, and today's installment takes us to Istanbul's Belgrade Forest, where Turkey's leading wild mushroom expert has found some remarkable fungus specimens.

It’s October and mushroom season in many parts of Europe, but if you were hoping for anything like Genoa’s Porcini Festival in Athens, you’re out of luck. But don’t despair: ‘shrooms, wild and cultivated, can be found; it just takes a little sleuthing.

In Mexico, the land of eternal spring, something good to eat is always in season. We ravenously await the arrival of artichokes in March, mangos in April, fresh corn in September. Even the wriggly little gusanos de maguey (maguey worms) which appear in May are wildly anticipated – by some. Change in season is subtle here, but essential to the survival of the country. But seasonal lines are blurring. Asparagus rears its tasteless Chilean head all year; pallid strawberries are found in December. Seasons have gone global and our palates suffer for it. Which is all the more reason to pay attention to what’s local now. From July into October, coinciding with our temporada de lluvia, wild mushrooms, spurred on by rain and humidity, hit the markets of central Mexico. Here in the capital, the month of August is high ‘shroom time.

Being a vegan would be a lonely business in Brazil if it weren’t for one handy catch – even the beefiest, chicken-heart-gobbling, butter-on-white-bread carioca likes giving his digestive track a day off on occasion. That’s why Jan Carvalho’s veranda-turned Vegana Chácara is popping every weekday at lunchtime. His version of feijoada, the Brazilian national dish, replaces the traditional pork parts that provide the richness in the black bean stew with smoked tofu and shiitake mushrooms. A regular client of his, a musician, jokes that Carvalho’s is the only one he can eat two helpings of and still play soccer afterward. “Eighty percent of my clients are not vegan,” says Carvalho. “They’ll go and eat at a churrasco” – cookout – “afterward.”

Kifisia, as we’ve mentioned before, used to be a holiday destination for wealthy Athenians, and its suburban charms remain intact. Green spaces, high-end shops and close proximity to most of Athens’ international schools have seduced a number of expats into settling down here. We’ve written previously about the original Nice ‘n’ Easy in Kolonaki; it’s one of the few non-smoking establishments in a city where everyone puffs up all the time.

The brothers Altu and Erol Aslan, who operate the Yeni Melek corner store on Ayhan Işık Sokak in Istanbul’s Beyoğlu neighborhood, have a legitimate complaint against their next-door neighbor, Tarihi Kalkanoğlu Pilavcısı. The shop – morning, noon and night – really does reek of butter. For those unfamiliar with the preferred cooking agent of the eastern Black Sea, where the neighbor in question hails from, this isn’t the sort of bland whitish grease that comes from the Land o’ Lakes; it's a funky yellow mass that is bused in from the villages around Trabzon in unmarked buckets like contraband.