Based on examples from the exhibition "Archi20/21: Intervening on 20th century architecture", the guided tour questions the interventions of the 21st century on buildings built in the 20th century according to 8 postures: enlarge, renovate, reconvert, maintain, leave as is, demolish, restore, move. A posture is then developed more precisely on the building of the Atrium of Vichy, former bottling plant.