The city of Kronstadt is located on the island of Kotlin in the Gulf of Finland.
The construction of the fortified city of Kronshtadt began in 1703 with building Fort Kronshlot (in translation - the Crown Castle) near the island. The purpose of the fortress was to close the fairway, which leads to the mouth of Neva. May 7, 1704 the fort and two batteries began functioning. A month later, a squadron of Swedish ships tried to break past Kronshlot, but did not succeed. In 1709 construction of marinas, harbors, and warehouses for the fleet began. At the cost of many human lives, the first harbor was completed as soon as possible in 1714, and in 1723 the Merchant, Forest, Middle, and Military harbors began to fuction.
In 1723, the construction of the central fortress, known as Kronstadt - "Crown City" - began. The palace of Peter I and the palace of A.D. Menshikov ("Italian palace") were built on the seashore.
Immediately after the construction, the Kronstadt Fortress became a reliable shield of Russia and St. Petersburg. According to Peter's plan, Kronstadt was meant to be a part of the capital of Russia, so the best architects were invited to work on it: D. Trezzini, S.I. Chevakinsky, V.I. Bazhenov. As a result, a unique fortress and harbor was built.
The construction and development of fortifications continued in Kronstadt until the beginning of the 20th century. The unique complex of forts of Kronstadt was constructed. Forts have lost their military significance, but remained the most powerful fortification complex on Baltic shore, created to protect St. Petersburg from a possible attack by enemies from the sea.
The squadrons equipped in Kronstadt won victories in battles at sea: in 1714 - at Gangut, in 1719 - at Ezel, 1720 - at Grengam, 1770 - at Chesma, in 1788 - in Gogland, in 1790 - in Krasnogorsk and the Vyborg battles, in 1807 at the Dardanelles and Cape Athos, in 1827 in the Bay of Navarino.
From 1771 to 1798, the Kronstadt housed the Naval Cadet Corps. Several famous Russian sailors graduated from there, among them F.F. Bellingshausen, I.F. Kruzenshtern, Yu. F. Lisyansky. Famous admirals served in Kronstadt: F. F. Ushakov, P. S. Nakhimov, V. N. Kornilov and many others.
The commercial harbor of Kronstadt was really important for Russia, because the goods from sea vessels were loaded onto barges for delivery to St. Petersburg there. The heyday of the harbor was during the years 1860-1880, though after the opening of the Sea Canal to St. Petersburg, Kronstadt had lost its significance.
Kronstadt has also been an important scientific center. For example, the world's first icebreaker Pilot was built here. A.S. Popov invented the world's first radio receiver in Kronstadt. In 1898-1918, a laboratory manufacturing a vaccine against plague functioned at the fort "Emperor Alexander I".
During the Second World War, in 1939-1945, Kronstadt played a crucial role in the defense of Leningrad. For 900 days, Kronstadt was sieged and departed from the whole country and Leningrad. The Baltic fleet based in Kronstadt provided access to the Baltic Sea for submarines.
Now Kronstadt is one of the districts of St. Petersburg, its population is about 35 thousand people. There are projects to create a free economic zone on the island.
In 1996, the fortified city was open to tourists.