Get on top of the 4th world’s largest cathedral. It’s the best viewpoint of the city. When buying a ticket, choose the one to the colonnaded walkway.
Location: 4, Isaakiyevskaya square, metro “Admiralteyskaya”
Open:  Daily 10:30 -17:30; 1th May - 31th October 18:00 - 22:30 
Closed: Wednesday 
Colonnade access: Daily 10:30 - 18:00; 1 May - 31 October 18:00 - 22:30; 
1 June - 20 August 22:30 - 04:30
Website: 
isaak.ticketnet.ru/en/