L’Enfant’s 1791 plan for Washington has been celebrated around the world. Its grand avenues, circles, squares and monumental layout has created an impressive international capital city. But like any city, D.C. has changed over the past two centuries. But a local architect, the Post reports, has determined that in the past century, the District has lost 22 miles of its original street plan.

Recent security threats have closed more streets around Capitol Hill and near the Federal Reserve and the World Bank. Since the 1995 Oklahoma City bombing and the Sept. 11, 2001, attacks, more and more streets have been shut to vehicles … and in some circumstances, pedestrians too.

But the Post notes that security threats haven’t been the only reason for L’Enfant’s plan to be mangled in parts. Federal office building construction, freeways, railroads have been to blame as well. L’Enfant’s plan for the city was reshaped in part by the McMillan Commission a century ago, which reshaped the monumental core and brought Union Station to Capitol Hill.

DCist remembers being able to drive in front of the White House on Pennsylvania Avenue. Since Sept. 11, there aren’t too many groups that are calling for street’s re-opening. The Association of the Oldest Inhabitants of Washington has been a consistent voice for the reopening of Pennsylvania Avenue (… and Klingle Road as well, but that is a whole different story). But now that the White House is reconstructing the 1600 block of the avenue into a pedestrian mall, DCist doubts that it will ever be reopened to general traffic.