Dexameni Square takes its name from the Greek word for reservoir, and for good reason. Beneath this leafy retreat in Kolonaki sits a 2nd-century water cistern built by emperors Hadrian and Antoninus Pius, part of a 25-kilometre aqueduct that channelled spring water from Mount Parnitha to sustain Roman Athens. The reservoir still opens once a year on Epiphany Day, when priests bless the city's waters.

But Dexameni's role as a gathering place runs deeper than plumbing. In the early 1900s, the square's cafés became a salon for Athens' literary and artistic elite. Writers Nikos Kazantzakis, Alexandros Papadiamantis and Angelos Sikelianos met here to argue and inspire one another, establishing a bohemian tradition that survives in the square's café culture today. From May to September, an open-air cinema operates from the cistern's rooftop terrace.

VoiceMap's self-guided audio tours trace Hadrian's vision for Athens through this reservoir, connecting Roman engineering to the city's transformation and explaining how an emperor's infrastructure project became a neighbourhood refuge.