"The old synagogue is that way,” says my guide Adi Mahler, overhearing a woman speaking Ivrit as she struggles to navigate the winding maze of streets in El Call, Barcelona’s old Jewish quarter.

As it turns out, she was searching for the Argentinian empanada place around the corner — another of the city’s hidden treasures, if not quite on the same historic scale.

Because while the Jews of Barcelona were expelled in 1391, a century before the rest of Spain, the last 15 years have seen a rising awareness of the city’s Jewish heritage.

“Eighty years ago, people would not have known the community was here,” says Mahler, who leads the Barcelona Dreaming Jewish history tours. “Now there are tour guides in the Jewish Quarter, telling their story; a recognition this is part of the city’s history.”

Best known for its modern attractions, whether that’s Gaudi’s modernist architecture or the revitalised waterfront and edgy street art, you barely need scratch the surface in Barcelona to discover layer upon layer of history stretching back two millennia.

Stepping into Plaça Sant Jaume, our tour starts in what was once the heart of the old Roman city with ancient columns from the temple to Augustus tucked a few streets away. The square’s medieval church and graveyard are also long gone, replaced by the City Hall and Palau de la Generalitat — itself built in part over the ruins of the Jewish Quarter, where one angled wall directed to Jerusalem still shows the location of the old “sinagoga poca” or small synagogue.

For most Jewish visitors, it’s the nearby sinagoga mayor which is the first stop. Reopened as a museum in 2002 after the building was first identified as an ancient shul in 1987, it’s one of the oldest in Europe.

Depending on how you interpret the remains of Fourth century Roman wall and 13th century documents signed by King Jaume I, it could even be Europe’s oldest. Today, there are no services — Barcelona has four other synagogues with current congregations — but occasional weddings and Barmitzvahs are celebrated in the small room housing a partial Torah from Morocco and menorah made by the descendants of Mallorcan Jews, the Xuetes.

Then, a few years ago, restoration work inside a shop on Carrer dels Banys Nous uncovered what’s believed to be a 12th century mikvah, the “new baths” giving the street its name. Currently used to store flower displays, you can visit whenever the homeware shop, named Oliver, is open.

As we wandered the area’s narrow alleys, the gates which once enclosed the Jewish inhabitants long gone, Mahler recounted the history of the community here as he pointed out those little details still to be seen; a carved Jewish stone inscription recalling a Sardinian rabbi, the gap for a mezuzah on a doorframe, the oldest building in Barcelona still inhabited, once home to the Ben Aderet family including the parents of the Rashba.

Stare closely at the stones around the Plaça del Rei — itself the site of Rabbi Nachmanides’ public debate on religion, and later the headquarters of the Inquisition — and you’ll see carved Hebrew letters. Taken from the Jewish cemetery of Montjuïc in the 16th century long after the community was expelled, Mahler points out that those who desecrated the graves have “unintentionally commemorated the Jewish story today” by putting them in the heart of the city.

It’s food for thought, and fuelled by one of those famous Argentinian empanadas, I continue my wanderings through history and the old town.

My second guide, trained architect Bernat Carrau from Context Tours, takes me back to the creation of Barcino by the Romans in around 10BCE. Their solid walls can still be seen near the cathedral, where optimists sell selfie sticks outside and an elephant gargoyle joins the more usual creatures on the rooftop. Then on through time to the powerful guilds who ran the medieval city with its Gothic palaces, many decorated with the emblem of St George, one of the patron saints of Catalonia, and dragon.

Tracing Catalonia’s slow decline from small empire stretching to Italy and Greece, to the 18th century when it lost its independence in the war of the Spanish succession, we discover too the scars left from the Spanish Civil War on the way — both metaphorical and literal, in the case of one building.

With independent Catalan flags flying from buildings around the city (look for the blue triangle with a white star over the official red and yellow stripes) along with a cultural renaissance kickstarted by Antoni Gaudi’s work and official recognition of the Catalan language last century, that particular battle continues today.

Fascinating though the old city is, it’s still only one face of Barcelona. From our central base in the Raval district, one of Barcelona’s trendiest areas thanks to its multicultural mix, street art and our own stylish hotel, Barcelo Raval, it’s only a short walk to plenty of more modern attractions.

One night we wander to Fabrica Moritz, a 19th century brewery, now converted into three different restaurants — including a wine bar and Michelin-starred option — plus shop selling takeaway beer brewed on site, and a buzzing main bar to eat and drink into the small hours.

A few minutes in the other direction lies La Rambla, Barcelona’s tourist heart and home to La Boqueria food market, as well as hordes of caricaturists lining the pedestrian centre.

At the end, Columbus stares out from his column towards the sea and Port Vell. Saving my weary feet, we hop on e-bikes from We Barcelona and cruise past sculptures by Lichtenstein and Gehry towards the beach and Barceloneta, where locals hang the district’s own flags from the balconies.

On through bar-filled El Born, another contender for the title of Barcelona’s trendiest quarter, we skip the Picasso Museum for the city’s most famous son: Antoni Gaudi.

After the weirdly wonderful shapes on Casa Batllo, drawing inspiration from the human skeleton and more symbolism courtesy of St George, whose dragon lurks on the roof, the unmissable finish is a visit to La Sagrada Familia.

As much a work of art as a place of worship, construction has already lasted for 135 years since the first stone was laid in 1882. It’s hoped the project will be finished in time to commemorate the 100th anniversary of Gaudi’s death in 2026, although the six central towers alone will take at least three more years.

With so much to discover here, it’s good to have a ready-made excuse to return to this fascinating city.

Check out our video from Barcelona on the JC YouTube channel