The construction of fortifications in the 1920-1930-ies on the western border of the USSR: “Stalin's line”

In article it is told about the construction of defensive works on the western border of the USSR which is carried out for the benefit of strengthening of defense capability of the country in 1920-1930 in connection with the accruing military threat. The main attention is paid to the characteristic of the strengthened areas in the Leningrad, Belarusian and Ukrainian military districts, as well as their operational use in the initial period of the Great Patriotic war.