For more than a century Maine Avenue was the main avenue of Washington. Creeks and canals made the southwest section of town an island city in itself. Ships were built and herds of cattle slaughtered there, and you could buy anything from sharp sand to sex at wholesale or retail.

In living memory there were four dozen steam tugboats standing by to tend the fleets of sailing ships that brought us ice from New England, building stone from Aquia Creek, barrels of wild ducks from the Eastern Shore, wines from France and silks from Cathay. The tugs also shifted floating whorehouses up and down the river in accordance with the ebb and flow of zeal among the law-enforcement authorities of Washington, Maryland and Virginia.

From Alexandria to Georgetown the upper river was so jammed with shipping that prudent passengers made peac with their maker before embarking. But in the space of little more than a generation, the railroads took over the freight hauling and the automobile took over the passenger traffic and the Potomac lapsed into a backwater almost as quiet as when the Indians had it.

The waterfront's considerably quieter now, too, but you still can catch a fish at Fort McNair or buy one from the fishboats, dine in style before strolling across the avenue to the theater, or board an excursion boat for sightseeing or dinner afloat. Or you can stroll along the esplanade observing the joggers and the boat people, and wondering why a memorial to the victims of the Titanic came to be installed in such an unlikely place.