Historic preservation is a professional endeavor that seeks to preserve, conserve and protect buildings, objects, landscapes or other artifacts of historic significance. Urban design practitioners have assigned the preservation of historic sites and properties varying levels of importance over the last century. However, the importance of maintaining a sense of context and understanding for the forms that preceded us has increased over the last thirty years for many reasons. The market, as well as the urban design discipline itself, has moved us to understand and appreciate that a site’s history and context is an integral part of urban planning.

Government has responded accordingly; the federal branch has established a process by which tax breaks are awarded to developers renovating historic sites, and many local governments have the power to permanently ban demolition of any structure with a certain level of historical significance.

There are now local and regional historical commissions charged with protecting local jewels of the past, though many buildings of the same typology were destroyed decades ago without concern.  In Philadelphia, the Historical Commission reviews any proposed change to properties on the Local Register of Historic Places, which prevents these property owners from making significant exterior changes without approval.  The Register is mainly comprised of individual properties, though there are “historic districts” that are protected, such as Society Hill.