The Barrier of Stone is a name that sounds like a medieval wall, though what is actually out here is a creature of the twentieth and twenty-first centuries: the great flood barrier that stretches across the Gulf of Finland to protect St Petersburg. The city has been flooded again and again since its foundation, because it sits at the mouth of the Neva on land barely above sea level, and when westerly storms push water up the gulf the river backs up and spills into the streets. The worst floods are remembered in literature, most famously in Pushkin's poem about the bronze horseman.
After decades of argument and long pauses in construction, a complex of dams, gates and navigation passages was completed across the gulf. The structure links the mainland north of the city with Kotlin Island and then runs on south to the other shore, with a ring road running along its top. Riding it is a distinctive experience. The road is wide, dead straight in long sections, and so exposed that you feel the weather in a way you never do on land. A crosswind can lean you a surprising amount, and the water on either side shifts from grey to green to near-black depending on the sky.
There are no hills and almost no bends, so this is not a road for those who want corners. What it offers instead is scale: the low outline of the fortress islands, the cargo ships on the channel, the distant towers of the city. Gulls and cormorants work the water, and in winter the ice makes strange plates and ridges.
Kronstadt, about six kilometres from the point, is the closest real town, and it has fuel, food and a surprisingly rich old centre of naval buildings, a great cathedral and canals. There are fewer services on the barrier itself, so arrive with a tank in good shape. Speed limits are enforced on this stretch, and traffic can be heavy with trucks, so treat it as a serious road and not an afternoon dawdle.