sentences:  In 1904 Sikupilli, the first residential suburb in Lasnamäe, was laid out.Sikupilli remained the main residential area of Lasnamäe until the construction of microdistricts started in the 1970s.Construction of pre-fabricated concrete apartment blocks under the concept of microdistrict, for which Lasnamäe is today best known, started first in 1973 and at a massive scale in 1977.