Suomenlinna is a sea fortress located in front of Helsinki on eight islands. It was founded in 1748. There are 6km of stone walls and 105 cannons there. In Suomenlinna there are 200 buildings including 6 different museums. About 800 people reside permanently in Suomenlinna. Several ferries run daily between Suomenlinna and Helsinki Market Place. Now-a-days it is one of the Unesco World heritage places in Finland.