Some interesting exhibition halls have been built in Turin to house exhibits for the centenary celebration of Italy's unification. In one, a prestressed concrete structure was built underneath a park. The hall is 26 feet below ground level and is 495 feet long by 226 feet wide. The side walls of reinforced concrete have footings and buttresses which reach into the clay foundation. The end walls are of glass and form the entrances which are reached by means of ramps and stairways. The other one was built for the International Labor Exhibition. The architect designed an unusual hall with columns which are cruciform at the base and taper out to circular at the top. Steel spokes extend from the tops to support the steel and vermiculite roof which is 82 feet above ground. The gallery is a thin ribbed reinforced concrete slab cast against ferro-cement forms. The ribs form a pleasing pattern in the ceiling. The whole exterior is glazed and furnished with a fine view of the foothill and the Alps.