The first and most vivid impression one has of Piraeus is its port: bustling, ugly and uninviting. Just a place you have to endure in order to get to your destination, usually a beautifully serene Greek island. Piraeus, however, is definitely an exciting place for anyone looking for a culinary adventure, as it is a melting pot of cultures with many interesting places hidden in the backstreets, away from tourists. The whole area next to Hadjikyriakeion for example, a girls’ orphanage built in the 19th century, is well known to locals for its humble, yet high-quality tavernas, serving fresh fish and simple meze all year round.

The late Greek shipping magnate Aristotle Onassis may be world-famous, but no one could have guessed that he would be the source of inspiration for a neighborhood kebab place in a residential suburb of Athens. Onassis, who was commonly called Ari or Aristos, was born in 1906 in Smyrna (now Izmir, Turkey), only to later flee with his family to Greece in 1922, during the Greco-Turkish War. Poor but with a grand vision and a great mind, he went on to become one of the richest and most successful businessmen in the world. When Vasilis and Panayiotis, who also own other successful eateries in town, opened their kebab restaurant Kyr-Aristos (kyr is short/slang for kyrios, which can be translated as “mister”) in spring 2013, they decided to name it after Onassis, a refugee from Smyrna, where kebab was a traditional food.

On a recent visit to the market of Sant’Antonio Abate, a pilgrimage site for fresh produce, we made friends with Salvatore, a young Neapolitan chef who was buying fruit and vegetables for his restaurant. We thought nothing of it until we bumped into him again, this time when he was buying fresh bluefish, the symbol and pride, he told us, of his restaurant. Our curiosity piqued, we asked where he worked. Mimì alla Ferrovia, he told us, a name we immediately recognized – it’s one of the custodians of Neapolitan gastronomic orthodoxy. And Salvatore Giugliano, an innovative young chef of 27, is now at the helm of this historic restaurant.

In an ideal world, all fish restaurants would be like Casa Ideal, with its fresh red mullet, proper fish stews with rice, lovely staff taking care of your orders and affordable prices. Also in an ideal world, we would have visited Casa Ideal much earlier. We first heard about the restaurant, which for 40 years has operated in the backstreets of Trafaria on the south bank of the Tagus River, some time ago but never made the time to stop in for a bite. Yet after learning that the restaurant had changed hands a year and a half ago – 54-year-old Conceição Augusto took over from her sister and brother-in-law, and now runs Casa Ideal with her cousins Gabriela Carmo, who works in the kitchen, and Delfim Carlos Gomes, who works behind the counter – we decided to check it out.

Cal Pep is a name you’ll find across Barcelona, but it takes on a different meaning depending on which neighborhood you’re in. In Gràcia, the name Cal Pep is synonymous with an old bar-bodega, dedicated almost entirely to the business of drinking (Carrer de Verdi, 141). The Cal Pep in Born is a famous seafood restaurant in Born (Plaça de les Olles, 8), with lines snaking out the door. In Sants, Cal Pep is affixed to a charismatic bodegueta (small bodega). Narrow, long and dimly lit, this particular Cal Pep has the atmosphere of a wine temple – including wooden casks and a vintage fridge – that has been frozen in time, with most of the original decorations from 1927 still intact.

Surely Plateia Viktorias is one of the last places you’d look if you wanted to find a typical seaside taverna. The square, once a meeting place for Patission Avenue’s haute bourgeoisie in the first half of the 20th century, was filled with refugee tents and sleeping bags just a few years ago. Today it still boasts the city’s largest concentration of refugee help centers, and women with head scarves push prams through it, while Syrian and Afghan lads lounge on its ledges playing with their cell phones. We first noticed the eatery, at the very end of a two-block pedestrianized street called Hope (Elpidos), while on our way to lunch at the Victoria Art Project, an initiative born during last summer’s Documenta 14 art festival to foster creativity in the neighborhood.

The diverse bay of the Sado River estuary, with its old port towns, cork oak groves, ancient rice fields, beaches and wildlife, is only around 45 minutes south of Lisbon, but feels a million miles away from the Portuguese capital. The history of this region – which includes the slightly gritty main city of Setúbal – goes back to Roman times, and it has had a strong connection to the ocean ever since. Fish salting has been key to Setúbal’s economy from the first century onwards, with port activities developing in the 15th century and later more industrial development, particularly fish canning, in the 19th century.

The sleepy residential neighborhood of Melissia, which lies northeast of downtown Athens and under Mount Pentelikon, is a rather unlikely place to visit. The suburb doesn’t have any notable sites, and apart from Kozi’s, a lovely South African meat restaurant, there’s not much in the way of distinguished restaurants. So in 2012, when Ornel ‘Oli’ Mingo opened Psarokokkalo in the suburb, everyone though he was crazy. “People told me that there’s no way clients will come here to eat. But I saw potential. The rent was relatively cheap and there was some space for tables outside,” he explains. Fast-forward six years and Psarokokkalo (which means “fish bone” in Greek) has tripled in size, taking over the adjacent shop, and is now a beloved seafood taverna that attracts customers from all over Athens.