Fort Alexander is located in which body of water?

Fort Alexander, also Fort Alexander I, or Plague Fort is a naval fortress on an artificial island in the Gulf of Finland near St. Petersburg and Kronstadt. From 1899 to 1917, the fort housed a research laboratory on plague and other bacterial diseases.

Since the formation of Saint Petersburg in 1703, the waterways in the Gulf of Finland were of strategic importance for Russia. Peter I initiated the construction of forts in the Gulf of Finland and directed the foundation of the first military installation on the island of Kotlin, Fort Kronshlot, in 1704. Throughout the following two centuries, Russia continued to fortify the area.

The Gulf of Finland is the easternmost arm of the Baltic Sea. It extends between Finland to the north and Estonia to the south, to Saint Petersburg in Russia to the east, where the river Neva drains into it. Other major cities around the gulf include Helsinki and Tallinn.