 Helsinki's epithet, "The White City of the North", derives from this construction era.Helsinki is also home to numerous Art Nouveau-influenced (Jugend in Finnish) buildings belonging to the Kansallisromantiikka = romantic nationalism trend, designed in the early 20th century and strongly influenced by "Kalevala", which was a common theme of the era.Helsinki's Art Nouveau style is also featured in central residential districts, such as Katajanokka and Ullanlinna.