Athens

What's there to say? Athens is a big, dense, ugly, horribly polluted metropolis housing about half of Greece's population (5 million of the 10 million people). It does however, have the spectacular ancient treasures of the Acropolis (the Parthenon, Erectheon, etc.) and the National Archeological Museum, with antiquities from all over the Greek Isles, including the ancient mural of a spring day from Akrotiri (on Santorini, theorized by some experts to be the fabled Atlantis). Some of these artifacts date as far back as the 12th century B.C.!