The Panorama is not the first model of New York. In 1845 E. Porter Belden, a savvy local who had written the best city guide of its day, set 150 artists, craftsmen, and sculptors to work on what an advertisement in his guide described as "a perfect facsimile of New York, representing every street, lane, building, shed, park, fence, bee, and every other object in the city." This "Great w0rk of art," Belden said, distilled "over 200, 000 buildings, including Houses, Stores and Rear-Buildings" and two and a half million windows and doors into a twenty-by-twenty-four-foot miniature that encompassed the metropolis below Thirty-second Street and parts of Brooklyn and Governors Island, all basking under a nearly fifteen-foot-high Gothic canopy decorated with 0il paintings of "the leading business establishments and places of note in the city." Alas, every trace of it has vanished. Of course Belden’s prodigy was far from the first display of model buildings. Since antiquity architects and builders have used miniatures m solve design problems and win support from patrons and public. A recent show at die National Gallery of Art in Washington, D.C., featured fourteen models created by Renaissance architects, including the six-ton, fifteen-foot-high model of St. Peter’s that Antonio da Sangallo the Younger built for the pope. Beyond their uses as design tools and propaganda, models have always possessed a curious power to enchant and excite. The sculptor Teremy Lebensohn was describing architectural models but could have been characterizing all miniatures when he wrote, "The model offers us a Gulliver’s view of a Lilliputian world, its seduction of scale reinforcing the sense of our powers to control the environment, whether it be unbroken countryside, a city block or the interior of a room." A model 0fthe 1876 Philadelphia Centennial Exhibition presented to the city in 1889 is unique in that some of the buildings and details are made of brass and that it is still on display in the basement of what was the Liberal Arts Building at the fair in Philadelphia’s Fairmont Park. The San Francisco World’s Fair of 1915 featured another New York City model, 550 feet square and complete with a lighting system that highlighted the city’s major features. City models have also miniaturized Denver, San Diego, and San Francisco, the Denver one built during the 1930s with WPA funding. A re-creation of the city as it appeared in 1860, it includes figures of men, women, and children in period costumes, along with animals and assorted wagons, and is now on display at the Colorado History Museum in Denver. San Diego’s model, in Old Town State Historic Park, was built by Jo Toigo and completed in the 1970s and depicts that city’s Old Town section as it looked a century earlier. Like the Denver model, it includes people, animals and vehicles. A model of San Francisco is in the Environmental Simulation Laboratory in Berkeley, California. Not a realistic model in the true sense of the word, it represents the buildings and land contours of the city and has been used to study patterns of sunlight and shadow and the flower of wind caused by San Francisco’s many hills. The computer’s ability to simulate the same effects has diminished the model’s importance, and its future is uncertain. New materials and techniques have now brought the craft of architectural models to an impressive level. Computer-controlled lasers and photo-etching (the process invented to create the Panorama’s bridges) allow model makers to create presentations pieces of astonishing realism. What is the passage mainly about

A. City development in America
B. Famous American designers
C. History of American architecture
D. City model making in America