What is the 14th Century English Gothic structure at the Washington National Cathedral?

The architectural style in which the Washington National
Cathedral was designed and built is called Decorated Gothic. It is a style of
construction developed and used in England from roughly 1270-1380 (the 14th century).
The Gothic style of architecture made use of the pointed arch over doorways, windows,
and across the expanse of rooms.  This innovation allowed for wider aisles, larger
rooms, and thinner walls with much larger windows. Flying buttresses on the outside of
Gothic structures gave support to arches and columns, allowing for construction of
cathedral spaces that seemed to reach right to the heavens containing the God being
worshipped within the cathedral. Carved stone and wood, as well as stained glass and
tapestry, conveyed lessons about the history of the Church, the beliefs of the
worshippers, and the magnificence of God.