Final answer:
The giant thing that sits in the main courtyard of the Louvre is the Pyramid of the Louvre, a glass and metal structure designed by I.M. Pei.
Step-by-step explanation:
The giant thing that sits in the main courtyard of the Louvre is the Pyramid of the Louvre. The Pyramid is a large glass and metal structure that serves as the main entrance to the Louvre Museum. It was designed by the architect I.M. Pei and was completed in 1989. The Pyramid has become one of the most recognizable landmarks of the Louvre and is a popular attraction for visitors.