The Roman Agora (market) is just between Monastiraki and Plaka. It is less impressive than the ancient Greek Agora to the west, but it does have the extraordinary Tower of the winds which you can actually see without even entering the Agora as it is clearly visible from outside.
The Agora was built in the 1st century BC after a donation in 11 BC By Julius Caesar and Augustus, it is sometimes called the Caesar Augustus Agora. It was built to replace the ancient Greek Agora (market) which was hundreds of years old by Roman times and seen more like a museum or archeological site, much the same as we think of it today.
It contained pretty much the same type of things the Greek Agora had, colonnades, shops, fountains even public latrines.
The main entrance to the market is on the west side - The Gate of Athena Archegetis which still stands today.
There is also an eastern entrance - East Propylea, the four columns of this also still stand.
In the north of the Agora is the Fethiye Djami (mosque in Greek) a Turkish Mosque from 1456 AD that was built on an early Christian Basilica.
To the west of the Agora is the famous monument The Tower of The Winds. A 12 M (40ft) high 8 m (26ft) diameter building made out of marble was built in the 2nd century BC by Syrian Astronomer Andronikos Kyrrestes.
The building is actually a weather vane and water clock. Inside the structure is a complex system of water pipes and circular channels cut into the floor. There are also sundials etched into the bottom of the reliefs.
The tower takes its name from the external friezes of the eight winds on the outside of the structure.
It wasn't until the 17th century that it was correctly identified as a Horologion (water clock). Before this it was believed to be all kinds of different things, such as either the school or prison of Socrates and even the tomb of Philip II of Macedon.
On all eight sides of the tower are friezes of cherabes representing the wind from that direction. North - Boreas, North-West - Skiron, West - Zephyros, South-West - Lips, South - Notos, South-East - Euros, East - Apeliotes, North-East - Kaikias.
On the East and North side of the tower have holes to let light into the tower.
Location:The main entrance is on a small side street off Adrianou street, just east of the Stoa of Attalos.
Nearest Metro Station: Monastiraki.
Entrance Fee: 2 euros, but this and other sites are free if you buy the entrance ticket to the Acropolis and is valid for 7 days.
Opening hours: (summer) Tue - Sun 08:00 - 19:00. Monday - 11:00 - 19:00. (Winter) Tue - Sun 08:30 - 14:30. Monday - 11:00 -14:30. Closed on all public holidays.
Tips: Most of the Roman Agora can be seen from the road, especially its main attraction - The Tower of the Winds.