Elegant, historical Thissio seems an unlikely starting point for a street art tour. But after our guide, Rude, gives us his introduction, it soon makes sense. Not far from where we stand is a secret most passers-by miss: a depot where metro trains park up for the night. Peering inside, we can make out rows of metal trains covered with graffiti. Our guide reveals a little-known Greek connection to the birth of graffiti in 1970s New York. One of the most iconic tags that appeared on subway cars across the Big Apple, TAKI 183, was painted by a Greek called Dimitrios. His tag came from his nickname, ‘Dimitraki’, and his address, 183rd Street.

Our next stop is an old trolley bus depot — now an events space that’s covered in bold, colourful Wildstyle pieces and twisted characters, by street artists including Ino, Raiden, Jasone, Ozone and Kez. This derelict building was given a new lease of life in 2014 as part of Urban Act, a nationwide project that promotes artistic interventions in degraded public spaces.

The walls of the former Gazi gasworks, now a municipal arts centre, industrial museum, and innovation hub called Technopolis, have also been covered with towering murals inspired by the area’s industrial heritage. The murals show how buildings and even entire neighbourhoods can be re-energised through street art, turning forgotten and unwelcoming spaces into places where people actually want to hang out.