Kotlin Island

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Kotlin (Russian Котлин, Finnish Retusaari ) is a Russian island in the Gulf of Finland, 30 km west of Saint Petersburg in the Baltic Sea.

The fortified town of Kronstadt is located on the island, the "Petersburg dam " by the, is connected with a road embankment flood control function, with St. Petersburg's suburbs Lomonosov and Sestrorezk.

At the foot of the fortress is the Kronstadt level, which served as a height reference of the former Eastern bloc and until 1993, the GDR and the new federal states.