Athens on foot: the free hills and the 90-minute metro ticket

The old center is walkable: Plaka, Anafiotika's whitewashed lanes below the Acropolis, and the Monastiraki flea market are all within 20 minutes of each other. Filopappou Hill opposite the Acropolis has the classic postcard view and costs nothing, as does Lycabettus if you climb instead of taking the funicular. A single metro ticket is valid for 90 minutes across the metro, tram, and buses, and the airport metro ticket is a separate, higher fare.