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.
Shining Path 1992, the Shining Path has declined in activity. The common name of this group, Shining Path, distinguishes it from several other Peruvian communist parties with similar names (see Communism in Peru). The name is derived from a maxim of José Carlos Mariátegui, the founder of the original Peruvian Communist Party in the 1920s: ""El Marxismo-Leninismo abrirá el sendero luminoso hacia la revolución"" ("Marxism–Leninism will open the shining path to revolution"). This maxim was featured on the masthead of the newspaper of a Shining Path front group. Peruvian communist groups are often distinguished by the names of their publications. The followers