St. Petersburg invites tourists to private mansions
On April 21 in St. Petersburg, citizens and tourists will have the opportunity to make free excursions to mansions, usually inaccessible for free visit.
In particular, from 10:00 to 14:00 you can visit the house of A.F. Kelkh on Tchaikovsky Street, the Pulkovo Observatory, the building of the Russian Geographical Society in Grivtsov Lane, the house of M.P. Botkin, the fortress of Bip in Pavlovsk, the house of A.V. Pel with a pharmacy - one of the most beautiful buildings of Vasilievsky Island, as well as make walking tours "War of 1812 in the architecture of St. Petersburg" and around the island of New Holland. All excursions are timed to the International Day for the Protection of Monuments and Historical Places of UNESCO, and will be conducted by employees of the Committee for State Control, Use and Protection of Historical and Cultural Monuments (KGIOP) of the Government of St. Petersburg, as well as specialists of organizations using these objects.
Source: http://www.travel.ru/news/2012/04/17/200164.html