Bolshoi theatre is famous worldwide for its opera and ballet performances. If you are interested in classical and modern performances, this theatre would be a perfect choice in Russia!
NOTE: be careful and plan your visit in advance. Bolshoi Theatre is one of the most popular in Russia, so sold-out is very common practice. It is highly recommended to buy your ticket before you arrive to Russia.
You can check the schedule of performances and buy the tickets on the official website of Bolshoi Theatre: https://www.bolshoi.ru/en/timetable/
If you don't want to see the performance, you may take part in official tour inside the Historical building. They are held on Mondays, Wednesdays and Fridays (once in a day). A group of maximum 15 people is formed before the beginning of the excursion which starts at 11:15 am. The ticket office is situated in the Historical building (door number 12) and opens at 11 am (you cannot buy the ticket online). The price for the ticket is 1300 rubles. No children under the age of 14 are allowed.