The Physics Department dominates the Pupin Physics Laboratories, as one would expect, where it once conducted secret Manhattan Project experiments to help build the nuclear bomb. Less well known is that its original home on the Morningside Heights campus was Fayerweather Hall.
Today it mostly helps Columbia keep its Nobel Prize count high. The department once included Nobelists like Polykarp Kusch, I. I. Rabi and Enrico Fermi; now it has Nobelists TD Lee and Horst Stormer (who is actually joint with Applied Physics and Applied Mathematics in SEAS).
In case you were wondering, Brian Greene is actually a math professor.