Alston and Elivor Callahan owned a piece of property atop Red Mountain overlooking Birmingham, Alabama. The Callahans requested a house that would give them the sense of living in a control tower, similar to the one at Dulles Airport in Washington, DC, to overlook the city. Safdie's proposal comprised of a series of intersected cubes rotated at 45 degrees with the horizontal. The unique geometry with an elongated rectangular plan suited this unusual site. The design approach resulted in an extroverted yet transparent building that commands its surroundings.

Letter to Harvey Cushing from Cunningham Wilson, 812, Jefferson County Bank Building, Birmingham, Alabama, USA. Wilson compliments Cushing on his book, "Life of Sir William Osler."