The central market of Athens is located in Odos Athinas, the street that goes from Omonia to Monastiraki.
(42 odos Athinas).
It consists of an indoor market, for meat and fish, and an outside market for fruit, vegetables, eggs and alive animals. The market is open everyday only in the morning.
The indoor market is noisy, messy, colorful and an experience for the nose, some of the butchers there come from generations of butchers who owns stalls for more than a century.
If you are hungry there are two working class restaurants in the indoor market and a small restaurant under the vegetable market.
For more informations about the markets (Laiki) in Athens and their opening day, have a look at: AngloInfo