sentences:  In the Middle Ages some small hamlets were situated on the territory of present-day Lasnamäe.At that time Lasnamäe was mainly known for limestone quarries, as nearly the whole of Medieval Tallinn was built of local limestone.At the end of the 19th century, during the period of industrial expansion, some major factories were set up in Lasnamäe, including the Dvigatel factory, which had 2,260 workers in 1900.