EHT Traceries prepared a graphic history of the City Post Office for permanent display in the main historic lobby of the building. The firm was responsible for the concept development of the exhibition, acquisition of negatives and illustrations, preparation of text to accompany the graphic documentation, and coordination with the graphic artist firm that designed the exhibition.

The exhibition documents the building through its significant history, as the District of Columbia's main post office from 1911-1986, through its renovation and adaptive use in 1992. It highlights the importance of the structure as a product of the noted Chicago architectural firm of D.H. Burnham and Company, as well as an example of model post office planning and operation, and documents the extensive restoration effort involved in the rehabilitation of the building, including employing Italian craftsmen to execute all the missing interior carved marble, based on historic photographs and drawings. Today, the exhibition may be enjoyed by all visitors to the building.