Fort Alexander I

Fort Alexander I sits on an artificial islet in the Gulf of Finland with granite walls and multiple defensive layers. The structure features a circular layout with internal fortifications designed for naval protection.

The fortress was built between 1845 and 1850 as part of the defense system protecting Saint Petersburg from potential Baltic invasions. It served as a key fortification in a larger network protecting the region.

The fortress displays Russian military architecture through its circular design and granite walls from the 1800s. Visitors can observe how artillery positions were placed strategically throughout the structure.

Visitors take a boat from Kronstadt harbor to reach the island, where guided tours provide access to the fortification structures. It is advisable to wear weatherproof clothing since the location on the water can be quite windy.

After its military years, the fortress served as a research facility for the Imperial Institute of Experimental Medicine. Vaccine experiments were conducted here in isolation to study plague prevention.

Location: Kronstadt

Inception: 1845

Part of: Forts of the Gulf of Finland

Shares border with: Konstantin, Peter I

GPS coordinates: 59.98950,29.71780

Latest update: December 20, 2025 12:13