The Smolny Institute

I had heard about the Smolny Institute for the Education of Noble Girls for a long time, and on my recent visit to St. Petersburg finally got to see it (pictured above.) Originally a cathedral and convent, it was made into a girls' school by Catherine the Great in the 18th century. Modelled on the teachings of Voltaire (a friend of Catherine's,) it wasn't just a finishing school. Students were required to live there from age 5 to 18, and to study languages, mathematics, science and religion in addition to dancing and drama.
The Institute is also known for its architecture. It was designed by Rastrelli, who also designed the Hermitage in St. Petersburg, in neo-Classical style. Following the October Revolution of 1917, Lenin closed the school and used it as his government headquarters for some months. (He later moved his government's capital to Moscow.)
The Smolny is located on the main island of St. Petersburg, on its northeast corner somewhat far from most other attractions. Unfortunately it continues to be used for government purposes, and was not open when I was there in May. Normally a few rooms, which have been made into a museum, are open to the public.
If you are interested in Russian history and/or in the education of women (a noble endeavour,) it's a must on any visit to the Venice of the North.