This is probably the most esthetically satisfying large underground building to have penetrated American soil, though on approach there's almost nothing - arguably not enough - to see, certainly nothing that says "building". Gunnar Birkert's 1981 addition to the University of Michigan's Legal Research Building is part of the venerable 1920s Gothicized law school quadrangle, a visually homogenous complex including library, classrooms, and dormitories. The quad had, as it were, a piece missing at its southeast corner; and it is here under this missing element that Birkerts buried his building.
Oppenheimer Dean, Andrea. "'Splendor Beneath the Grass' in Michigan" AIA Journal 72, no. 1 (1983): 50-55.