Katri (Kaija) Anna-Maija Helena Siren (née Tuominen; October 23, 1920 in
Kotka – January 15, 2001) was a Finnish
architect. She graduated as an architect from the
Helsinki University of Technology in 1948. Siren designed most of her works together with her spouse to another Finnish architect,
Heikki Siren.
She and her husband Heikki Siren set up their own architectural office in 1949.
The Sirens worked together as architects their entire life. The
Otaniemi Chapel is noted for its delicate balance between features of Finnish rural architecture and a modernism, influenced by
Alvar Aalto's redbrick period of the 1950s. Their later work is noted for its monumentality.[1]