Some African objects had been collected by Europeans for centuries, and there had been industries producing some types, especially carvings in ivory, for European markets in some coastal regions. Between 1890 and 1918 the volume of objects greatly increased as Western colonial expansion in Africa led to the removal of many pieces of sub-Saharan African art that were subsequently brought to Europe and displayed. These objects entered the collections of natural history museums, art museums (both encyclopedic and specialist) and private collections in Europe and the United States. About 90% of Africa's cultural heritage is believed to be located in Europe, according to French art historians.