It is a church? Is it a castle? No, it actually is a museum, the National Museum of Finland, in central Helsinki.
The card was sent by Minna.
Photo Timo Syrjänen © Museovirasto
The National Museum of Finland presents Finnish history from the Stone Age to the present day, through objects and cultural history.
The appearance of the building reflects Finland's medieval churches and castles. The architecture belongs to national romanticism and the interior mainly to art nouveau. The museum was built from 1905 to 1910 and opened to the public in 1916. The museum was named the Finnish National Museum after Finland's independence in 1917. - in: wikipedia