Soviet 20-ton military manned space station, desined for photo and radio intelligence. It was equipped with several cameras, including infrared one and 1 meter camera "Agat-1". It also carried 23mm autocannon, which was tested in space just before deorbiting. It was the first and the only case of shooting in space. First concept supposed to use heavy cargo spacecraft TKS for resupply and crew rotation, but Soyuz was used instead. However, TKS was launched several times later uncrewed. Also ISS module Zarya is based on it.Hull of unfinished Almaz stations (development of equipment was slow) were used for first "civil" space station DOS-1. Both Almaz and DOS series were called Salyut for press.
Almaz space station by Sunder_59, on Flickr