Fort Constantine sits off the western end of Kotlin Island, out in the Gulf of Finland, and the sea is the whole point of it. Kotlin is a long, thin strip of land with the island city of Kronstadt at its heart, built by Peter the Great as the base of the Baltic fleet and the shield for St Petersburg. The forts around it were built on shoals and artificial islands to close the channels, which means several of them can only be seen from a distance, or from the water.
Constantine is one of the nineteenth-century coastal forts, from a time when the Russian empire expected attack from British and French fleets. After the Crimean War, when an Allied squadron nosed around the Baltic, the defences were reinforced. The forts are low, long and made of granite and brick, built to sit just above the waterline and present as small a target as possible. Their casemates, parapets and ruined gun emplacements bleach and grow mossy, a little like the bones of some sea creature, and the whole group has a melancholy that photographs rarely catch.
For riding, the flavour of this area is the long coastal approach, flat and straight, with grey water on one side and birch scrub on the other. There are very few corners. It is a ride about distance and sky, and about the cold wind that can shove a bike sideways without warning. Check the forecast before you commit, because fog and sea-spray can make the exposed shoreline unpleasant. Surfaces near the coast suffer from frost and salt, so potholes and patched asphalt are normal.
Kronstadt itself is a naval town with fuel and food. Access to the island and to some of the forts has varied over the years, so it is worth confirming what you can actually reach rather than assuming. The sea air carries salt and the faint smell of weed and diesel. Come in the long light of June or in September, when the water goes a deep slate colour and the old walls turn warm in the evening.