From the announcement:
It took the city’s office of historic preservation more than 15 years to make, covers 127,000 buildings, and it’s still not quite finished. If you like history, maps, weird old buildings, and killing time on the internet, you, my friend, have come to the right place. This week, Washington, D.C.’s Historic Preservation Office flicked the switch on their latest project—HistoryQuest DC, a truly magnificent interactive GIS map stuffed with info on some 127,000 buildings in the District, from the White House and the Capitol on down to the funkiest little alley rowhouse.
Read full announcement here.