On the left, issued on 24 April 2006 under the theme, Polish Cities. Czestochowa, a city name I'm not sure if I'm pronouncing properly. The city is famous as a place of pilgrimage. It houses the Black Madonna, credited for many miracles. The architecture too is evidently magnificent, at least for me -- judging from this stamp.
On the right, issued on 30 April 2013 under the theme, World Cultural Heritage of Russia, Historical center of Saint-Petersburg. This stamp features the Spit of Vasilyevsky Island. It captures one of the two Rostral columns and the Old Saint Petersburg Stock Exchange. Both structures are significant examples of Greek Revival architecture.
The theme for Sunday Stamps this weekend is city views. Check out other entries at See It On A Postcard for views of other cities from around the world.