Poznań is a city on the Warta river in west-central Poland, in the region called Wielkopolska (Greater Poland). After the second partition of Poland Poznań was administrated by Prussia, and then, with the unification of Germany after the Franco-Prussian War of 1871, the province of Posen became part of the German Empire. Furthermore, the city of Posen was officially named an imperial residence city, leading to the construction of the Imperial Castle, the Imperial District, the Opera House, new city walls, railway station and many other sites which make a big part of its landmarks to this day. Today, Poznań is an important cultural and business centre and one of Poland's most populous regions with many regional customs such as Jarmark Świętojański, traditional Saint Martin's croissants and a local dialect. More: en.wikipedia.org.