Palazzo del Lavoro was designed by Pierluigi Nervi for the 100th anniversary of the Unification of Italy. It features innovative and audacious building solutions, whose celebrating purpose couples with a high technological quality. Its size is impressive: it is a parallelepiped with square base having a 158-metre side, 25 metres in height and an overall volume of 625,000 cubic metres. The building peculiarities are the massive cross-shaped base pillars that are 25 m high and support huge steel capitals with radial geometry having a 40-metre side. The outer glazing walls are based on uprights which contribute to limit thermal expansions and discharge wind pressure on the covering. This building is safeguarded by the Superintendence for architectural heritage.