With new waves of development, other buildings must fall, or so say developers. Preservationists, on the other hand, would like to see the history of a city reflected in its architecture. These conflicting camps are constantly facing off at community board meetings and city halls around the country, so we've rounded up a dozen of America's most heated preservation battles. Some are under threat from development, while others suffer from lack of funding and, in one case, the unavoidable scourge of Mother Nature. From lost causes to reversals of fortune, they're all on the map.