I just returned from Greece where this view of the ancient city walls of Athens was too appealing to pass up. The archway shown here was where the Eridanos River emerged from the city at the Sacred Gate on Athens’ northwest side. This was immediately beside the mighty Dipylon Gate which was the major portal into the city, and through which the broad Panathenaic Way passed.
In the time of Classical Athens the Eridanos River was a significant source of water, though it dropped off considerably during the hot summer months. Today the volume has been reduced so much that it mostly flows underground. As you can see here, that is still enough to cause a bright green strip of growth among otherwise dry land.
This opening under the wall was protected by the high ramparts around it, which extended forward to form a narrow, watery passage where death could be rained down by soldiers above. These days it rests quietly in the Kerameikos district on grounds maintained by the city.
(image by Greeceguy)