Design Moment: Le Grand Louvre, 1989

When Chinese architect IM Pei’s pyramid opened, it was a magnet for controversy

To mark his 100th birthday last month, take note of one of Chinese architect IM Pei’s instantly recognisable and, at the time it was built, controversial works: Le Grand Louvre.

In the 1980s the Paris museum was becoming a victim of its own success: huge visitor numbers made the three entrances unworkable and access to the galleries difficult. Space to show the works of art was limited. The solution – and it was the era of president François Mitterrand's grand projets – was a design one, to radically change the entrance. There was no public competition; Pei, an American-trained architect, was asked to do it. His idea is the very definition of mixing old and new, a combination of the arrestingly visual and seriously functional.

Objections to it ranged from the nationality of its architect (not French) to its apparent cultural reference point (Egypt – much shrugging)

He redesigned the Cour Napoléon, the main square of the Louvre digging down to create a new underground system of galleries. But it was what was above ground that was the most startling: the enormous glass and steel pyramid designed to the same proportions as the Pyramid of Giza. It served as a new entrance with three smaller triangles to light the space below.

When it opened in 1989 it was a magnet for controversy in France, where objections to it ranged from the nationality of its architect (not French) to its apparent cultural reference point (Egypt – much shrugging) to its very modernity, its interior lights glowing like a beacon of change surrounded on three sides by the classical Louvre buildings. Bonkers theories about it soon sprung up. The most startling and persistent was that there are 666 panes of glass in the main pyramid. That one, with all its devilish baggage, even appeared in Dan Brown's The Da Vinci Code. Design historians have been quick to point out there are 675 diamond-shaped and 118 triangular panes of glass in the structure.