In our attempts to conserve our heritage buildings and sculptures made of limestone, we seek to understand the mechanisms of their degradation. So-called black crusts on limestone surfaces are the result of long term weathering as a result of air pollution. Micro-CT allows us to perform full 3D microscopy on the development of such black crusts and how it modifies the stone properties. State-of-the-art developments in temporal resolution allowed us to do such 3D research on crust development in real-time. You can see the first results of this dynamic X-ray CT imaging of limestone weathering, a collaboration between Prof. Tim De Kock and Tescan-XRE, on YouTube.