Acropolis in Athens

When the Athenians fled their city, before Xerxes and his Immortals could reach (and sack) it, they waited-out events in their triremes.  When they saw smoke rise above the acropolis, they would not have seen the Parthenon - today one of the most famous landmarks in the world.  In 480 BC, the famous temple to Athena had not yet been built.