The Silver Cloud spent 3 full days in St. Petersburg and docked in the city. We were able to see a lot....even attended a performance of Swan Lake at the fabulous Mariinsky Ballet. Reason enough to book this cruise.
We weren't interested in entertainment or activities, except for attending the excellent lectures on upcoming destinations every evening.
The only glitch in the whole experience....and this was minor....was that the embarkation in Stockholm was very near the ferry terminal, and our taxi took us to the wrong place. We ended up walking a few blocks, feeling confused. It would have been helpful for Silversea to point out the possible confusion, as we weren't the only ones with the issue.