On and after August 24, 1912, there shall not be erected on any reservation, park, or public grounds, of the United States within the District of Columbia, any building or structure without express authority of Congress.
D.C. Code § 10-128
When authorization by Congress needed for building
Aug. 24, 1912, 37 Stat. 444, ch. 355, § 1
Official source: D.C. Law Library (Council of the District of Columbia). Reproduced from public-domain District of Columbia statutes; confirm against the official source for the current text. Not legal advice.