If you're eager to add a bit of extra culture to your getaway, put The Benois Family Museum at Peterhof State Museum Preserve on your list. Check for guided tours or just look around at your own pace.
This Lomonosov museum is a good spot to kick off your day of sightseeing. There's lots to see close by, like Peterhof Palace and Garden, Kronstadt Fortress, and Petrovsky Park. Take your time at The Benois Family Museum at Peterhof State Museum Preserve before making tracks to these other fine attractions.

