Gediminas' Tower is the remaining part of the Upper Castle in Vilnius, Lithuania. The first fortifications were built of wood by Duke of the Grand Duchy of Lithuania, Gediminas. Later the first brick castle was completed in 1409 by Grand Duke Vytautas. Third floor tower was rebuilt in 1930, by Polish architect Jan Borowski. Some remnants of the old castle have been restored, guided by archeological research.