One major concern at Pompeii is that by excavation and revealing the building ruins, we've exposed them to the destructive forces of nature. Just to illustrate how the house has changed in the last century, this is a photograph of essentially the same location as the previous one, taken about 1900 by Giorgio Sommer.
Seems a bit odd to complain about the damaging effects of rain, wind and tourists on the ruins of Pompeii, which was protected for 1,750 years by ash fall from a volcanic eruption.
Sources
For more on the archaeology of Pompeii, see Pompeii: Buried in Ashes.
Beard, Mary. 2008. The Fires of Vesuvius: Pompeii Lost and Found. Harvard University Press, Cambridge.
Christensen, Alexis. 2006. From palaces to Pompeii: The architectural and social context of Hellenistic floor mosaics in the House of the Faun. PhD dissertation, Department of Classics, Florida State University.
Mau, August. 1902. Pompeii, Its Life and Art. Translated by Francis Wiley Kelsey. The MacMillan Company.


