The Roman Forum is located north of the Acropolis in Athens. If you are walking in the ancient Agora you could wander into the Roman Forum without realizing the difference. The Tower of the Winds in the Roman Forum might have been seen by the Apostle Paul during his stay in Athens (Acts 17:15-34).
The Tower of the Winds was built about 40 B.C. by Andronicus to serve as a sundial, water-clock, and weather-vane. Fant and Reddish describe the structure this way:
… the Tower of the Winds on the east side of the forum, named for the reliefs of the Eight Winds on the frieze about the top of the tower. Originally the tower was a complete ancient weather station, designed by a famous Macedonian astronomer, Andronikos of Kyrrhos. Sundials were mounted on the exterior sides of the building, a water clock operated inside the tower, and the bronze weather vane on top indicated the wind direction over the applicable image of one of the Eight Winds. (A Guide to Biblical Sites in Greece and Turkey, 32)
In the photo below you will see the Tower of the Winds on the right in the Roman Forum. The hill in the distance is known as Mount Lycabetus. It is the highest point in the city of Athens.
Here is a larger image of the Tower of the Winds.