Trubetskoy bastion (Saint Petersburg)

 fortification, 18th century construction, bastion (fortification part)

This pentagonal defense fortification with two front walls (faces) and two side walls (flanks) for frontal and flanking fire was named after Peter the Great's associate Yury Trubetskoy, who supervised the construction.
Designed by architect and fortification engineer Domenico Trezzini, the bastion was built in stone in 1708-1709 to replace an earth and wood structure. The riverfront facade was faced with granite slabs in 1781-1785 designed by engineer Roman Tomilov. In the right-hand face wall there was a secret tunnel for safe troop movements between the casemates.
In the first quarter of the 18th century, the casemates were used as torture and prison cells by the Secret Chancellery. Peter the Great's son, Tsarevich Aleksey, was held here in 1718. From 1724 to the mid-19th century, the bastion was affiliated with the Mint. In early 1826, 25 solitary cells were appointed in different parts of the fortification for the Decembrists. In 1870-1872, the inner walls and casemates were dismantled, and a new political prison was built.
The bastion is currently affiliated with the State Museum of the History of St Petersburg.