The embassy's interior, showcasing the art of 59 artists from the United States, is organized as two "bars" of office space, joined by an atrium in the center, visible as the tall structure seen from the outside. The design of the building took several years. The architect spoke about the challenge presented by the design project in the wake of the Oklahoma City bombing in 1995. It forced him, he said, to move the atrium to the centre of the building, and the glass wall facing Sussex Drive, which had been intended as a fully transparent curtain wall, would now disguise a concrete blast wall with smaller windows punctuating the concrete. Interior furnishings in the atrium area feature "Niagara blue" a colour chosen to "reflect the shared experience, close relationship and free trade association between the United States and Canada — Niagara blue because of the shared beauty of Niagara Falls."