The airport was designed by local architect Joseph W. Hoover. One of the features of his style is the use of simple, exposed concrete, steel, and glass materials. The terminal building was constructed in "stepped" levels: the first floor extended farther than the second, the second floor extended farther than the third, etc. Such a design meant that the uncovered roof of the lower level could be an observation deck. In addition to the observation decks, the rounded "Horizon Room" was on the fourth floor with a commanding view of the airport. The interior of the terminal building was in the contemporary International Style, as was the exterior. One of the memorable features of the lobby was the large compass laid in the floor with green and yellow-orange terrazzo. A mobile by Alexander Calder was another decorative feature of the lobby. The mobile hangs in the center core of the new airside terminal. A re-creation of the compass was installed in the new terminal at an exhibit dedicated to old "Greater Pitt".