Athens Marathon. Classic and Authentic. The 35th Athens Marathon,The Authentic took place on Sunday, November 12. The run begins in the town of Marathon where it passes the tomb of the Athenian soldiers. It is the most difficult marathon race, the course is uphill from the 10km to the 31 km – the toughest uphill climb of any major marathon. The finish line is in the Panathinaiko Stadium, venue for the first Olympic Games of the modern period 1896.