Geometric Shape
For the entrance to the subterranean level, Pei wanted to avoid it looking like a mere subway station and he needed the right kind of building to draw visitors to the museum's entrance. A solid concrete structure - like his East Building of the National Gallery of Art in Washington DC - was out of the question, since this would clash with the classical facades of the Louvre palace.
After studying the works of André Le Nôtre - France's great landscape designer - who strictly followed geometric patterns, Pei came up with the shape of a pyramid, which would form a beacon at the center of the courtyard. He opted for a glass cladding since this would be the least intrusive and it would also allow light to enter the foyer below.