Kronstadt (Russian: Кроншта́дт, romanized: Kronshtadt, IPA: [krɐnˈʂtat]) is a Russian port city in Kronshtadtsky District of the federal city of Saint Petersburg, located on Kotlin Island, 30 km (19 mi) west of Saint Petersburg, near the head of the Gulf of Finland.

It is linked to the former Russian capital by a combination levee-causeway-seagate, the St Petersburg Dam, part of the city's flood defences, which also acts as road access to Kotlin island from the mainland.

Founded in the early 18th century by Peter the Great, it became an important international centre of commerce whose trade role was later eclipsed by its strategic significance as the primary maritime defence outpost of the former Russian capital.

[4][5] The main base of the Russian Baltic Fleet was located in Kronstadt, guarding the approaches to Saint Petersburg.

The historic centre of the city and its fortifications are part of the World Heritage Site that is Saint Petersburg and Related Groups of Monuments.

Just as Kronstadt became populated and fortified, it attracted merchants from maritime powers most notably, the Dutch, the British and the Germans through the old Hanse connections.

They settled both in Kronstadt and in St Petersburg itself and for a time dominated both inward and outward trade, especially in the reign of Catherine the Great.

The old three-decker forts, five in number, which formerly constituted the principal defences and had resisted the Anglo-French fleets during the Crimean War, became of secondary importance.

During the civil war, the sailors participated on the red side, until 1921, when they rebelled against Bolshevik rule in the Kronstadt rebellion.

Despite this, the cruiser Oleg was torpedoed and sunk by a small motor boat after participating in the bombardment of Krasnaya Gorka fort that had revolted against the Bolsheviks.

[10] This was followed on August 18, 1919, by a raid of seven Royal Navy Coastal Motor Boats inside the harbour of Kronstadt itself, damaging the Soviet battleships Petropavlovsk and Andrei Pervozvanny, and sinking a submarine supply ship, the Pamiat Azova.

In 1921, a group of naval officers and men, together with soldiers and civilian supporters, rebelled against the Bolshevik government in Soviet Kronstadt.

The duty officer, first lieutenant S. Kushnerev, ordered anti-aircraft batteries to open fire on enemy planes.

Twenty-seven German planes took part in the first attack, and three were destroyed by the anti-aircraft guns of the 1st Air Defence Regiment of the Baltic Fleet.

Hitler was enraged, because Soviet submarines frequently disrupted military supplies of strategic materials from Sweden to Germany.

For the protection of Leningrad 10 brigades of naval infantry, four regiments, and more than 40 separate battalions and companies were formed in Kronstadt.

Several sections of the yard were destroyed, the docks were heavily bombed causing the death of dozens of workers and engineers.

Thanks to the power of the Kronstadt Fortress the destruction of Leningrad, then the main industrial and cultural centre of the Soviet Union, was successfully prevented.

With changing historical trends, the population saw peaks and troughs partly determined by the expansion and then decline of the naval base and dockyard.

This monitoring was necessary because the water level of the Finnish Gulf could change considerably in a short time, creating problems for shipping.

All depths and altitudes (even the heights of spacecraft) in Russia and some other countries of the former Russian Empire are measured according to the Kronstadt sea-gauge.

The modern city's most striking landmark is considered to be the enormous Naval Cathedral, dedicated to St Nicholas and built between 1908 and 1913 in Anchor Square which also contains many military memorials.

There are a number of historic buildings, such as the Dutch Kitchen and the former Italian Palace, that recall the city's mercantile and military past.

Some fortifications were located inside the city itself and one was on the western shore of Kronslot Island, on the other side of the main navigational channel.

[13] The now demolished older St Andrew Cathedral (1817), once a prominent Kronstadt landmark, was destroyed on Communist orders in 1932.