On a crisp spring afternoon my 16-year-old son Ned and I left the Acropolis, strode through the Agora, and headed down the remains of the Panathenaic Way towards Piraeus and beyond in the footsteps of so many legendary Athenians. Every now and then modernity intervened: a railway track has long since sliced off a sliver of the Agora; a few hawkers lined the upper reaches of the ancie