The white marble building and annex of the Pan American Union, within broad lawns set with trees and shrubbery, form an integral yet distinctive part of the group monumental buildings gradually developing along Seventeen Street and Constitution Avenue. The architectural significance of the Pan American Building lies in the blending of North and South American styles, symbolic of a common understanding of the republics of the Western Hemisphere. The Pan American Union was founded upon this principle of united interests, and represents the most ambitious efforts yet made to maintain and forward the social, economic, and cultural interrelationships of the two Americas.
The Pan American Union is an international organization created and maintained by Argentina, Bolivia, Brazil, Chile, Columbia, Costa Rica, Cuba, the Dominican Republic, Ecuador, El Salvador, Guatemala, Haiti, Honduras, Mexico Nicaragua, Panama, Paraquay, Peru, the United States, Uruguay, and Venezuela. Each of these 21 countries make financial contributions in ratio to its population. The affairs of the Union are administered by a Director General and an Assistant Director, elected by and responsible to the governing board composed of the Secretary of State of the United States and the diplomatic representatives in Washington of the other American Governments...
A plan to erect a building in Washington was approved by the Union in 1903 and a few years later Andrew Carnegie attracted by the ideals of the association gave $900,000 of the $1,100,000 needed. The remain sum was contributed by the countries directly interested. The architects were Albert Kelsey and Paul P. Cret
The Pan American Building represents an exceptionally fortunate solution of a complex architectural problem. The site is one of unusual importance, facing the Ellipse on one side and Constitution Avenue on the other. The plan of the building involves a number of exacting practical requirements. But the most severe challenge of the skill and imagination of its designers was the significance of the edifice as a monument symbolizing the amity of North and South America. All three elements of the problem were resolved in an architectural conception of great freedom and distinction.
In style of the structure represents a felicitous combination of French and Spanish Renaissance influences, with a free admixture, certain interior decorations, of Aztec and May motifs. The main facade, facing Seventeenth Street, combines the formality of a public building with the romantic dignity of a great villa or a colonial governor's palace. Based upon a well-integrated and carefully balanced composition, the building is distinguished by the richness, vitality, and ingenuity of its decorative treatment. The themes of North and South American motifs are everywhere skillfully blended and harmonized, and the ornamental details throughout are well conceived and handsomely executed.
The principal facade is approached by a circular drive and a low flight of steps, flanked by great bronze lanterns, leading up to a central arcaded entrance framed by lofty pylons. Against the pylons are two marble groups, each of a moth instructing a youth. On the north pylon the group typifying North America is the work of Gutzon Borglum. The group opposite is the work of Isidore Konti and is representative of South America. Ave the corresponding pylons are bas reliefs depicting North and South American historical scenes, and above these are a North American eagle and a South American condor, the work of Solon Borglum. The bases of the pedestals serve as fountains, and the balustrades above the pylons are derived from the cathedral in Chihuahua. - Washington, City and Capital, 1937, pgs. 343-348.
The above quotation is from a six page section in the Guide on the Pan American Union. The Pan American Union is now known as the Organization of American States and it continues to be headquartered in this building. The organization has now grown to 35 nations though at this time Honduras and Cuba are not participating. Most of the new members are newly independent nations of the Caribbean along with the addition of Canada. The building description is much as described in the Guide.