Mentioned by washington.org
Where to Get the Best Views of the Washington, DC Skyline | Washington DC
"The gorgeous architecture of the Washington National Cathedral is reason enough to head way up Wisconsin Avenue. Daily self-guided tours showcase the cathedral’s history and intricate architectural details. But if you want to experience perhaps the best rooftop view in the city (located on a hill, the cathedral claims the highest point in DC), you’ll want to book the Tower Climb tour."