As someone who is used to how Canada and United States work where you buy your groceries from a grocery story, going to visit a market in foreign countries is always a treat since you get to see how things operate elsewhere. Mind you, they do have grocery stores as well, but the atmosphere, price, and quality differ significantly.
The Central Market is about a 15 minute walk from Syntagma Square, you'll find fresh meats and fish in the Central Market. It is a market open to the public and you will see stalls upon stalls filled with what I assume are the catches of the day. Mind you, you will walk past 5-10 stalls that all sell the same thing with the same prices, but still worth seeing my mind. Note, the market isn't for the faint of heart. You will see a lot of blood (and liking be walking in blood soaked tile), and some recently killed animals that they are butchering on the spot. We did notice that there weren't fresh seafood, which was a bit odd.
When you are done, just across the street is the fresh produce market which is outside and not covered, however, you can find all the fruits and vegetables that you desire, as well as shops that sell essentials like oils, spices, herbs, etc.
Sorry for slacking off, I'll try to maintain my usual schedule again. Come back next Friday for another Past Point of Interest!