Underground parking of only two levels was considered an innovative concept in 1964, when developer Louis Lesser developed a two-level underground parking structure under six 10-storey high-rise residential halls at California State University, Los Angeles, which lacked space for horizontal expansion in the university. The simple two-level parking structure was considered unusual enough in 1964 that a separate newspaper section entitled "Parking Underground" described the parking lot as an innovative "concept" and as "subterranean spaces". In Toronto, a 2,400 space underground parking structure below Nathan Phillips Square is one of the world's largest. Parking which serve shopping centers can be built adjacent to the center for easier access at each floor between shops and parking. One example is Mall of America in Bloomington, Minnesota, USA, which has two large parking lots attached to the building, at the eastern and western ends. A common position for parking within shopping centers in the UK is on the roof, around the various utility systems, enabling customers to take lifts straight down into the center. Examples of such are The Oracle in Reading and Festival Place in Basingstoke. Parking Garages without mixed use can provide excellent uses for the Roof area: The Grove Parking Garage is the site for movies on its 8th level roof, The Grand Prix of Long Beach, CA can be viewed from the Roof level of The Aquarium of the Pacific Parking Garage and The Pike Parking Garage (opposite the Queensway Structure) were built with a thickened post tensioned roof slab to accommodate crowds of people. These parking structures often have low ceiling clearances [7'-2" and 8'-4" for accessible parking], which restrict access by full-size vans and other large vehicles. On 15 December 2013, a man was killed during a robbery in the parking garage at The Mall at Short Hills in Millburn, New Jersey. The paramedics responding to the shooting were delayed because their ambulance was too large to enter the structure. In the United States, costs for parking garages are estimated to cost between $25,000 per space, with underground parking costing around $35,000 per space. Structural integrity Parking structures are subjected to the heavy and shifting loads of moving vehicles, and must bear the associated physical stresses. Expansion joints are used between sections not only for thermal expansion but to accommodate the flexing of the structure's sections due to vehicle traffic. Parking structures are generally not subject to