I am attaching 3 pictures related to Marathon. The place that in 490 BC the Athenians won their first victory over the Persians. The first 2 are of the gulf where the Persian fleet had anchored. The third is of the burial mound for the Athenians that fell in the battle. The Marathon run starts just outside of the lot that the mound lies and ends in the stadium in Athens. Distance 42 klms. As to the significance of the battle here is a quote from Wikipedia.
The battle was a defining moment for the young Athenian democracy, showing what might be achieved through unity and self-belief; indeed, the battle effectively marks the start of a "golden age" for Athens. This was also applicable to Greece as a whole; "their victory endowed the Greeks with a faith in their destiny that was to endure for three centuries, during which western culture was born". John Stuart Mill's famous opinion was that "the Battle of Marathon, even as an event in British history, is more important than the Battle of Hastings". It seems that the Athenian playwright Aeschylus considered his participation at Marathon to be his greatest achievement in life (rather than his plays).
