Courtesy Rogers Stirk Harbour + Partners

Decades before Renzo Piano, Hon. FAIA, and Richard Rogers, Hon. FAIA, earned their respective Pritzker Prizes, the duo—now of Renzo Piano Building Workshop, in Paris and Genova, Italy, and Rogers Stirk Harbour + Partners in London—designed the Centre Pompidou in Paris after winning the French Ministry of Culture's competition in 1971 with Gianfranco Franchini. The iconic 10-story steel building opened 40 years ago today, and first welcomed the public on Feb. 2, 1977.

Centre Pompidou is among the earliest projects listed in each firm's extensive online portfolios. "The Centre Pompidou brings together the themes which have characterised Rogers’ architecture from the mid 1960s – skin and structure, technology and flexibility, movement and anti-monumentalism," notes Rogers' firm. Piano's firm compares the inside-out structure to a spaceship: "The centre is like a huge spaceship made of glass, steel, and coloured tubing that landed unexpectedly in the heart of the Paris, and where it would very quickly set deep roots."

The firms are recognizing the milestone on Twitter this week, and ARCHITECT collected a few of the comments below.