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.
Acanthus mollis Acanthus mollis Acanthus mollis, commonly known as bear's breeches, sea dock, bearsfoot or oyster plant, is a herbaceous perennial plant with an underground rhizome in the genus "Acanthus". It is regarded as an invasive species in some jurisdictions. The name of the genus derives from the Greek name of the plant "ákanthos"; it was imitated in Corinthian capitals. This "ákanthos" is related to "ákantha" meaning "thorn" referring to the thorn-bearing sepals, or any thorny or prickly plant in Greek. The Latin name of the species, "mollis" meaning "soft, smooth", refers to the texture of the leaves. "Acanthus mollis" reaches on