Ice Cruise of the Baltic Fleet
1918 CE.
Shown on the map at 58.617°, 20.417°.
The Ice Cruise of the Baltic Fleet (Russian: Ледовый поход Балтийского флота) was an operation which transferred the ships of the Baltic Fleet of the Imperial Russian Navy from their bases at Tallinn, at the time known as Reval (Russian: Ревель), and Helsinki to Kronstadt in 1918.
Text from the Wikipedia article Ice Cruise of the Baltic Fleet, licensed CC BY-SA 4.0.