The Colosseum was built of brick and clad in travertine. After the fall of the empire, much of the travertine was appropriated for use in other Roman buildings. Some believe that travertine quarried from the Colosseum was used in the construction of St. Peter's Basilica. The English word "dilapidated", meaning "run down," derives from this practice. "Lapidi" in Latin means "stones." To "de-lapidate" something means to remove the stones.