36 CFR § 910.13 - Urban design of Washington, DC.

(a) Pennsylvania Avenue's unique role as the physical and symbolic link between the White House and the U.S. Capitol should be reinforced by new development along it.

(b) To reinforce and enrich the legacy of the L'Enfant Plan, the primary function of new development in the Development Area is to define open spaces and plazas, or to reinforce vistas along major streets and thoroughfares.