When Rudy Ricciotti and Mario Bellini’s “flying carpet” opens on September 22, it will be the largest intervention in the Musée du Louvre's former palace complex since I. M. Pei plunged pyramids into its central courtyard in 1988. And like Pei, the Franco-Italian duo also had to go underground with their addition. They placed 32,000 sqaure feet of exhibition space for the museum's collection of Islamic art beneath an undulating horizontal screen that spreads across an internal courtyard without touching the surrounding landmarked facades.

A free-form lattice composed of 8,000 steel tubes and glass covered by a gilded metal veil, the canopy covers a below-grade exhibition space, where glass vitrines display objects inside the vast open-plan gallery. From there, a monolithic staircase descends into a second subterranean exhibition space. Ricciotti and Bellini clad the stair and walls in the lower level with a 2.5-inch-thick layer of black concrete—formulated specifically for the project—which appears to glow as the exhibition lighting reflects off of its oil-like sheen.

The project required the painstaking excavation of the courtyard down to some 40 feet without disturbing the palace’s original foundations. “In the end, it was mainly about putting the Islamic arts on a pedestal and creating a natural dialogue between the new department and the older building,” says Ricciotti. “We wanted to multiply the possibilities for interaction between the existing facades and the modern floating structure to force a respectful cohabitation.”