If you have been enthusiastic enough to travel to Venice to visit St Petersburg, you should travel 30km to the Russian Versailles called Peterhof.
Peterhof Palace has a huge garden and a magnificent palace building. On hot summer days, the rush is especially huge but it’s worth it. In any case it’s best to spend a whole day there. Like almost everywhere in the tourist regions of Russia, you have to pay double the admission fee as a foreigner. However, students pay less than normal adults, so students, do not forget to bring your student card! The best of Peterhof (in my opinion) are the thousand fountains and the view of the Gulf of Finland, but the golden roofs of the palace buildings are also not to be missed! Amazing!