Below the traffic of modern Athens lies a second city: water tunnels cut more than 2,500 years ago, buried streets and an ancient river that still flows. The tunnels themselves are closed to the public, but you can see a surprising amount of underground Athens for the price of a metro ticket: in station halls, under the glass floors of the Acropolis Museum and at a Roman reservoir in Kolonaki.
Underground Athens at a glance
- Where: across central Athens, at Syntagma, Monastiraki, Evangelismos and Acropoli metro stations, beneath the Acropolis Museum and on Dexameni Square in Kolonaki.
- Built: from the aqueduct of Peisistratos, around 540–530 BC, to Hadrian's aqueduct, begun in AD 125 and completed in AD 140.
- What it is today: ancient tunnels that are mostly closed to visitors, with sections, pipes and finds on display in metro stations and an excavated ancient neighbourhood under the Acropolis Museum.
- Time needed: a few minutes per metro station; 1–2 hours to combine the stations with the museum excavation.
Water tunnels from Peisistratos to Hadrian
Ancient Athens was always short of water, and its rulers solved the problem underground. Around 540–530 BC the tyrant Peisistratos had an aqueduct built to bring water from springs at the foot of Mount Hymettus into the city. For most of its length it ran as a tunnel, up to about 14 metres deep, carrying clay pipes some 20 centimetres wide with joints sealed with lead and oval openings so the pipes could be cleaned.
Seven centuries later the Roman emperor Hadrian, a great admirer of Athens, began a far longer aqueduct in AD 125. It was completed in AD 140 under his successor Antoninus Pius and ran underground for roughly 20 kilometres from the foothills of Mount Parnitha to a reservoir on the slopes of Lycabettus, at today's Dexameni Square. After falling into disuse, it was repaired in the 19th century, when the new Greek capital was short of water, and served the city into the 20th century. In recent years Athens has begun drawing non-drinking water from it again.
What to look for
- Syntagma station: a cross-section through the layers of the city from the 5th century BC to the Ottoman period, with a burial, a mosaic floor and water pipes, including a branch of the Peisistratos aqueduct.
- Monastiraki station: the enclosed bed of the ancient Eridanos river, which still flows beneath the square.
- Evangelismos station: clay pipes of the Peisistratos aqueduct from the late 6th century BC, believed to belong to the main line.
- Acropoli station: replicas of sections of the Parthenon frieze and figures from the east pediment showing the birth of Athena, plus cases of finds such as children's toys and amphorae.
- The Acropolis Museum excavation: through glass floors you look down on an ancient neighbourhood of roads, houses, baths, workshops and tombs, used from the 4th millennium BC to the 12th century AD.
- Dexameni Square in Kolonaki: Hadrian's reservoir is not open to visitors, but you can see part of its interior through openings in its western wall.
The metro that became a dig
When Athens built its modern metro in the 1990s, every shaft and station cut through history. The work turned into the largest archaeological project in Greece, with more than 50,000 finds, and lines 2 and 3 opened in 2000 with some of those finds displayed in the stations. That is why several stations now work as small free museums for anyone passing through.
Tips for your visit
- Visit the stations outside rush hour, so you can stop at the display cases without blocking commuters.
- At the Acropolis Museum, look down through the glass in the forecourt: part of the excavation is visible even before you go in.
- Do not go looking for ways into the tunnels: they are closed, unlit and unsafe. Everything worth seeing is on show in the stations and the museum.
- Combine Dexameni Square with a walk up Lycabettus hill, which starts just above it.
Nearby
- The Acropolis: the Parthenon and the other temples on the rock above the museum.
- The Ancient Agora: the market and civic centre of ancient Athens, a short walk from Monastiraki.
- Kerameikos: the ancient cemetery, where the bed of the Eridanos river can be seen in the open air.
- Hadrian's Library: the remains of the emperor's library complex right next to Monastiraki station.
See Athens with World City Trail
Our Athens scavenger hunt turns the old town into a game you play on your phone. The route links 10 stops and takes around 2 hours, with about 50 minutes of walking, around the Acropolis and the Acropolis Museum. You can play in English, German, French, Italian, Spanish, Dutch and Greek.
If you prefer a different format, there is also a self-guided walking tour and an outdoor escape game in Athens.
Play the Athens scavenger hunt →
Take the self-guided walking tour of Athens →
Play the outdoor escape game in Athens →
Facts checked in October 2026.