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.
Ophrys insectifera dark in colour, varying from maroon to black and on which there are two shining 'pseudoeyes' as well as an iridescent blue/grey patch evolved to resemble an insect's glistening wings. Chromosomes 2n=36 The genus name ""Ophrys"" derives from the Greek word "ophrys", meaning eyebrow, while the Latin epithet "insectifera" means insect-bearing or insect-carrying, referring to the unusual appearance of the flowers. It is native to Europe, favouring sites with damp, alkaline, unimproved soil. It can be found growing in beech woodlands, on forest edges, in scrub, on limestone pavement, limestone grassland, in chalk pits and wet meadows as well as