The Tower of the Winds, a small octagonal marble tower at the edge of the Roman Agora, is one of the most remarkable surviving buildings of Greek antiquity — and probably the most overlooked. Built around 50 BCE by the astronomer Andronikos of Kyrrhos, it combined a sundial on each face, a wind vane on the roof, and a water clock inside. It is the world's first surviving meteorological station.
The carved reliefs of the eight winds, each in characteristic dress, are remarkably crisp 2,000 years later. The tower survived the Roman, Byzantine, and Ottoman periods almost intact, in part because each successive ruler found it useful enough to leave alone. The interior is open to visitors with the Roman Agora ticket.