Monastiraki is where Athens feels most alive. The small square at its centre, overlooked by the stripped-down Tzistarakis Mosque (now a ceramics museum), is a permanent crossroads of backpackers, vendors, and locals. The flea market spreading through the surrounding streets is best on Sunday, when antiques, junk, and everything in between spill out across the pavements.
The Roman Agora, just east of Monastiraki, holds the Tower of the Winds and the Gate of Athena Archegetis — the entrance to the old market quarter of the Roman city. The nearby Hadrian's Library is another large Roman complex worth a look. Both are on the combined Acropolis ticket.
Several rooftop bars in Monastiraki offer some of the best Acropolis views in the city, particularly at sunset. The meat shops and souvlaki stalls on Mitropoleos Street are the classic Athens cheap lunch — a paper-wrapped souvlaki or gyros from one of the counter-only places is hard to beat.