It's no secret: New York is changing and changing quickly.

Classic neighborhoods are constantly endangered by rapid overdevelopment; historic structures routinely fall victim to the wrecking ball.

A certain measure of this is inevitable in such a dynamic place. But, in an effort to prevent the indiscriminate razing of beloved Big Apple institutions, the city passed the 1965 New York City Landmarks Law. The legislation's success has helped define and maintain the authentic and charming character of some of New York's most cherished locales.

And a handful of New Yorkers have made it their mission to protect historic buildings, streets and other structures from developers and decay. We found preservationists throughout the five boroughs and spoke to them about their community's biggest successes and the sites in their neighborhoods that need to be saved.