Los Angeles City Hall was completed in 1928 by a three-firm collaboration between John Parkinson, John C. Austin, and Albert C. Martin Sr. At 138 metres it was, at the time of its completion, the tallest building west of the Mississippi, and it would remain the tallest building in Los Angeles for the next thirty-six years.
The composition is a strict classical tripartite vertical scheme. A colonnaded base of five storeys, articulated in academic Beaux-Arts language, supports a tall, regularly fenestrated shaft. The shaft rises through twenty-two further storeys, with corner setbacks at the upper levels, and is capped by a stepped pyramidal crown surmounted by a small classical tholos with a lantern. The pyramidal cap is a deliberate quotation of the Mausoleum of Halicarnassus, one of the seven wonders of the ancient world, and the choice declares the building’s monumental ambition. The structural system is reinforced concrete clad in cream-coloured terra-cotta. Decoratively the building is a hybrid: the lower colonnades and pediments belong to Beaux-Arts academicism, but the detail at the upper shaft and the geometric ornament around the windows is plainly Art Deco. The concrete itself was symbolically composed, mixed with sand from every county in California and water from the twenty-one Spanish missions of the state. Until 1956 a height limit of 150 feet (about forty-six metres) applied to all other buildings in Los Angeles, an ordinance that effectively protected the silhouette of City Hall from competition for a generation. As a result the city developed horizontally rather than vertically during its formative twentieth-century decades.
City Hall was retrofitted between 1998 and 2001 with one of the largest base isolation systems in the world, capable of decoupling the tower from the underlying ground motion during a major earthquake. The retrofit is invisible from the street but allows the building to survive a magnitude 8.2 event with minimal damage. Few civic monuments in the country sit so explicitly at the intersection of nineteenth-century classical iconography and twenty-first-century seismic engineering.