New Orleans, with its richly mottled old buildings, its sly, sophisticated - sometimes almost disreputable - air, and its Hispanic-Gallic traditions, has more the flavor of an old European capital than an American city. Townhouses in the French Quarter, with their courtyards and carriageways, are thought by some scholars to be related on a small scale to certain Parisian "hotels" - princely urban residences of the 17th and 18th centuries. Visitors particularly remember the decorative cast-iron balconies that cover many of these townhouses like ornamental filigree cages. European influence is also seen in the city's famous above-ground cemeteries. The practice of interring people in large, richly adorned above-ground tombs dates from the period when New Orleans was under Spanish rule. These hugely popular "cities of the dead" have been and continue to be an item of great interest to visitors. Mark Twain, noting that New Orleanians did not have conventional below-ground burials, quipped that "few of the living complain and none of the other." The spine of Uptown, and much of New Orleans, is the city's grand residential rue, St. Charles Avenue, which was aptly described in the novel "A Confederacy of Dunces": "The ancient oaks of St. Charles Avenue arched over the avenue like a canopy... St. Charles Avenue must be the loveliest place in the world. From time to time... passed the slowly rocking streetcars that seemed to be leisurely moving toward no special destinations, following their route through the old mansions on either side... Everything looked so calm, so prosperous." The streetcars in question, the St. Charles Line, represent the nation's only surviving historic streetcar system. All 35 electric cars were manufactured by the Brill & Perley Thomas Company between 1922 and 1924 and are still in use - truly a national treasure. Creole cottages and shotgun houses dominate the scene in many New Orleans neighborhoods. Both have a murky ancestry. The Creole cottage, two rooms wide and two or more rooms deep under a generous pitched roof with a front overhang or gallery, is thought to have evolved from various European and Caribbean forms. The shotgun house is one room wide and two, three or four rooms deep under a continuous gable roof. As legend has it, the name was suggested by the fact that because the rooms and doors line up, one can fire a shotgun through the house without hitting anything. Some scholars have suggested that shotguns evolved from ancient African "long-houses," but no one really knows. It is true that shotguns represent a distinctively Southern house type. They are also found in the form of plantation quarters houses. Unlike shotgun houses in much of the South, which are fairly plain, New Orleans shotguns fairly bristle with Victorian jigsaw ornament, especially prominent, florid brackets. Indeed, in many ways New Orleans shotguns are as much a signature of the city as the French Quarter. One of the truly amazing aspects of New Orleans architecture is the sheer number of historic homes and buildings per square mile. New Orleanians never seem to replace anything. Consider this, Uptown, the city's largest historic district, has almost 11,000 buildings, 82 percent of which were built before 1935 - truly a "time warp." New Orleans' architectural character is unlike that of any other American city. A delight to both natives and visitors, it presents such a variety that even after many years of study, one can still find things unique and undiscovered.