The Church of the Holy Trinity is an Orthodox church designed by Carl Ludvig Engel, consecrated in 1827. The church is Empire style and serves the large Russian-speaking minority of Orthodox in Helsinki, partly because the other Orthodox churches in the city have held their services in Finnish. The top of the church's bell tower was originally made of wood, but twenty years after its construction it was rebuilt in the present stone when new heavy bells were added to the church.
The Cathedral of the Assumption, or Uspenski Cathedral, is the cathedral of the Orthodox Diocese of Helsinki. It was built by order of Emperor Alexander II of Russia between 1862 and 1868. It was designed by the architect Alexis Gornostaiev (1808-1862), one of the founders of the Russian Revival architecture. The crypt hosts a variety of events, including exhibitions and lectures on ecclesiastical art and ecclesiastical artefacts.
The German church was built in 1864 and designed by Harald von Bosse and C. J. von Heideken in the neo-gothic style. The church burnt down in 1958 and was then repaired according to the plans of architect O. Hansson. Between 1997 and 2001 the church underwent a major renovation, modification and extension of the buildings, designed by architects Juha Leiviskä and Rosemarie Schnitzler.