Limestone high quality quarried limestone, called Indiana limestone. Many famous buildings in London are built from Portland limestone. Limestone was also a very popular building block in the Middle Ages in the areas where it occurred, since it is hard, durable, and commonly occurs in easily accessible surface exposures. Many medieval churches and castles in Europe are made of limestone. Beer stone was a popular kind of limestone for medieval buildings in southern England. Limestone and (to a lesser extent) marble are reactive to acid solutions, making acid rain a significant problem to the preservation of artifacts made from this stone.
Gorgon Gorgon In Greek mythology, a Gorgon (; plural: Gorgons, "Gorgon"/"Gorgo") is a mythical creature portrayed in ancient Greek literature. While descriptions of Gorgons vary across Greek literature and occur in the earliest examples of Greek literature, the term commonly refers to any of three sisters who had hair made of living, venomous snakes, as well as a horrifying visage that turned those who beheld her to stone. Traditionally, while two of the Gorgons were immortal, Stheno and Euryale, their sister Medusa was not and she was slain by the demigod and hero Perseus. The name derives from the ancient Greek