Peter the Great wanted a palace by the sea that would rival Versailles, and he chose this stretch of the southern shore of the Gulf of Finland, about thirty kilometres west of Saint Petersburg. What became Peterhof is a town built around an imperial residence: the Grand Palace on a terrace above the sea, the Grand Cascade of gilded statues and fountains falling toward a canal that runs straight to the water, and parks full of pavilions, including Peter's own small Dutch style house, Monplaisir, right on the shore. The fountains run on gravity, fed by springs on the higher ground inland, a feat of eighteenth century engineering.
The town itself grew around the palace, with churches, barracks, villas and a nineteenth century cathedral of Saints Peter and Paul in red brick. During the Second World War Peterhof was occupied and badly damaged, and much of what you see today was painstakingly restored after 1945. The Prioratsky Park, nearby, contains a curious palace built for the Order of Malta in the late eighteenth century, made of compressed earth.
The road from Saint Petersburg runs along the coast, busy with traffic, buses and tourists, especially in summer. It is not a great ride in itself, but the views over the gulf are lovely, and Kronstadt, the naval fortress town on an island, is reachable via the dam that crosses the gulf. Further west, Lomonosov, formerly Oranienbaum, has another palace and park.
Arrive by boat if you can bear to leave the bike for a few hours: hydrofoils run from the city centre in summer and land at the pier at the foot of the canal, which is how many people first see the cascade, framed by the palace above.
Practical matters for foreign riders in Russia are complicated at present, with travel advisories, insurance and payment restrictions to consider, so check the current situation carefully before planning any trip. Fuel and services are plentiful in Peterhof and the surrounding towns. The fountains generally run from late spring to early autumn, and the parks are busiest on weekends and holidays; early morning is the best time to visit.