RARE Former Soviet USSR Pin

Rare former USSR pin "The Rumyantsev Obelisk 1798-1799" The Rumyantsev Obelisk is a granite obelisk located in Saint Petersburg. It is at the centre of Rumyantsev Square, on Vasilyevsky Island, between the Menshikov Palace and the Saint Petersburg Institute for Painting, Sculpture and Architecture. - Leningrad / St-Petersburg - Memorial in Saint Petersburg - Румянцевский Обелиск 1798-1799 - Russian language - Vintage - Marked С/Л (?... not sure) and 10k on the back - 1.5" high 18.10