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 Stone Community Action in 2002; the co-founder and president is Song Qinghua. The NGO closely cooperates with national and foreign foundations including Canadian Harmony Foundation, German Konrad-Adenauer-Stiftung, Chinese Vantone Foundation, and American Ford Foundation. The organization also carries out pilot projects and gives trainings on behalf of Chinese authorities (e.g. Chinese Ministry of Civil Affairs and Beijing Hepingli Sub-District). The American Ford Foundation has supported SCCA's mission and activities since the founding of the NPO in 2002. Shining Stone Community Action Shining Stone Community Action (SSCA; Chinese: 社区参与行动) is a Beijing-based non-profit organization whose mission is to engage citizens in public decision making.