"Expansion" is a monumental welded steel sculpture by César Baldaccini, created in 1968 and installed at the La Défense business district in Paris. The work exemplifies César's signature style of manipulating industrial materials, featuring a dynamic composition of crushed and compressed metal forms that appear to burst outward, symbolizing growth and urban development. Standing as a landmark public artwork, the sculpture demonstrates the artist's ability to transform raw industrial materials into a powerful expression of movement and energy.