Once in the village Kosmozero, which consisted of three villages Demidova, churchyard and artifacts built a beautiful church ensemble. In the 18th century Kosmozersky parish had about 90 yards and a little more than 700 souls. Himself architectural ensemble consisted of the Assumption Church, the bell tower and the church of Alexander Svirsky, and was one of the nicest in the area.

Both churches were built on the principle of "octagon on the quadrangle." Since the 17th century, this principle was widely used in the construction of churches in Russia. Further, following a similar style of construction, the entire ensemble of the church was covered with a high wooden tents, including a small bell tower, built in the 30s of the nineteenth century near the lake.

Surprisingly, the picture of the three majestic tall tents could see the traveler, suitable for Kosmozero. The composition of the Onega tee is so amazing that every time when approaching from different directions experience gives multifaceted architecture of temples. Before the eyes of the viewer, it then merges into one fabulous picture with incredible contours, it appears separately, clearly showing every building.
Church of the Assumption, built in 1720, was a warm winter and much smaller than the church of Alexander Svirsky. It was restored several times, removing the wood paneling of the nineteenth century. Fully restored traditional facade and roof replaced hip, has been retained in this prichelina decorated with carvings. Looking at a wood carving, unwittingly struck by the work of skillful carpenters. No wonder their skill perfected, handed down from generation to generation. Indeed, in ancient times, a simple but smooth hewn board already has a decoration of any home, because this effect is only achieved with the ax. Later, hewn edges of the boards started to decorate uncomplicated designs. After the appearance of tools such as chisels and drill, patterns become more complicated. Original designs could be obtained, bonding different patterned planks with nails.

Summer church of Alexander Svirsky, was built in 1770 by order of merchant F .  Popov from St. Petersburg .  The church was a log, and the walls are built with shallow Povalii .  On the east side extension was performed five walls of the altar, which in turn was covered with a roof pyatiskatnoy .  And on the west side was attached - a spacious dining hall and the porch of the main entrance to the church .  The entire ensemble was the western gable roof covered with multi-level complex and tackless design .  Log in to the church can be had with the southern and northern sides of the open area with stairs .  Octagon building consisted of a two-tier belt, lower and stayed not completed .  The roof of the church of the tent is made of planed planks, arranged in three rows of beautiful ornament .  At the end of the roof put a cross covered with shingles .  Decorative finishing the altar represented as colored red planks, with tanned truncated endings - peaks, as well as the facade of carved boards, adorned windows of the church .

The arrival at the time of the church year called for - Svirsky. But because of the weather conditions were there from May to September. It has survived not all church ensemble. Some buildings were irretrievably lost in a fire in 1942. The remaining part is not only the cultural and historical value, but also architecture, belonging to Prionezhsky type tent churches.