12 hours in Athens

Well, the three most important sites in Athens are the Parthenon and Agora, the Parthenon museum, and the National Archeological Museum. The most important neighborhoods to visit in that time would be Monastiraki and the Plaka. On a 12 hour excursion you could probably do the Parthenon Museum and Parthenon, Agora and one of the neighborhoods. I wouldn't plan any more than that. You'll have to factor in transportation time too. I hope this helps some.

In Athens it depends a bit on what you mean by 'all the sites'.

For example the Keramicos is well worth a visit if you haven't already been. A nice site in its own right and good views up to the Acropolis.

http://en.wikipedia.org/wiki/Kerameikos

I'd also recommend a walk up Filopappou, the next hill over from the Acropolis. It's pretty much unvisited by tourists and you get dramatic views back across. We've written up our favourite walk there about half way down this page

http://www.greekramblings.org.uk/Exploring_Athens.html

Both of these are walkable, assuming you are reasonably fit, from Thisseo metro station which is 20 minutes on a direct metro line from Piraeus.

The view from Mount Lycabettus is also spectacular

http://en.wikipedia.org/wiki/Mount_Lycabettus

Here your best bet is probably to get the metro to Syntagma, walk up through Kolonaki (Athen's high fashion district) and then get the funicular railway up.

Have a great day.

Alan

Thanks Alan - I'll have a look at your recommendations. I should have said the main tourist sites - while the Acropolis is a must see - I have seen it and no desire to do it again. I'm hoping for a "wow" experience which wasn't present the first visit.