While the Alexandria in Egypt remains on my fantasy Great Civilizations tour, Alexandria, Virginia is also pretty neat. Interestingly, both Alexandrias are named for Alexanders - but ancient Alexandria (named for Alexander the Great) was actually built upon a MORE ancient Ptolemic city, while more modern Alexandria (once named Belle Haven) was based on the estate of Philip Alexander II who was contemporary to the founding of modern Alexandria in the 1600's. [For some excellent reading on Alexander the Great, see Mary Renault's The Persian Boy.]
But I digress. While I was in National Harbor, a waypoint was Alexandria. The train station and the water taxi were 2 or 3 miles apart, eminently walkable. The path between the two was King Street, which passes through and largely comprises "Old Town" (lovely cobbled side streets proved an attractive diversion though!) The waterfront is attractive and well-used by tourists and city dwellers alike - but what really attracted me were the many lamp posts and fabulous door knockers!