All materials irreversibly change their properties under the influence of weather and environment. Carrara marble loses the cohesion among its crystals and increases its porosity. These changes completely penetrate the sculpture and are an indication of its individual history. Ultrasonic investigations are a good means to measure the decohesion and the extension of porosity in marble. Comparative investigations of originals and copies of Carrara marble sculptures in the Potsdam Park of Sanssouci and in the Bode Museum of Berlin show that the destruction of original sculptures in the museum is similar to that of the copies in the Potsdam Park of Sanssouci.