Once it was a private collection of Russian emperors who could buy any masterpiece of world art at any price, but today this 2nd largest art museum in the world is open to everyone. It will take several years to observe all collections of the Hermitage, because the total number of exhibits exceeds 3 million. However, even one excursion, especially in company with an experienced guide, is enough to see the most famous parts of the exhibition:
In order to avoid standing in the queue you should buy e-tickets via Excurzilla, thus you save time and see the maximum number of masterpieces at a time.
See also other sights in St. Petersburg: Wieliczka Salt Mine, Wawel Castle, Schindler’s Factory Museum