The plot tells about the simplest bomb shelters of the local air defense - earthen "cracks". Moscow, July 6, 1941 A group of Stakhanovites and workers in Moscow inspect the layouts of field-type shelters "slots" at the permanent All-Union construction exhibition. "Gaps" are a means of collective protection of residents of settlements, as well as workers and employees of industrial facilities in an attack from the air. "Slit" provides sheltered protection from bullets, shrapnel, from an air shock wave during the explosion of air bombs, from debris during the destruction of neighboring buildings, as well as from liquid droplets of poisonous substances. The shelters are camouflaged with improvised means, the normal capacity of the "gap" is 10-12 people, the largest is 40 people. The architect Vsevolod Nikolayevich Konstantinov explains to the tourists the principles of building shelters, the tourists listen attentively to the architect. Muscovites are building earthen "cracks" on the outskirts of the city. General view of construction. General view of the constructed shelter. A group of Muscovites goes out into the street from a ready-made shelter, they are met by V.N. Konstantinov.