Hi everyone

I read from lonley planet guide that there's a new 15 euro tourist ticket, valid for 3 days, allows unlimited travel on all public transport? anyone knows where i can buy the ticket? I just arrive Athens by ferry today, the staff at the Piraeus Metro station said they know sell this 3-day ticket, but couldn't answer my question where I could get it, the staff at EOT is not helpful either... or do you think I need to buy this ticket as I stay at Syntagma district, are all sightseeing spots within walking distance?

your prompt reply is much appreciated. thanks.