The ensemble of the Senate Square is decorated with the symbol of Helsinki - Lutheran Cathedral before St. Nicholas Cathedral. Above the church rises the central dome and sculptures of the 12 apostles. This building began Engel, and another German architect Ernst Lohrmann, added its four towers with domes and gold crosses. Annexes are not very strict harmony with the general style of the building. Indoors, drawn up in the Protestant ascetic, attracted the attention of the statue of Luther, Melanchthon and Mikael Agricola.

During the construction of the cathedral was formed at the bottom of a high cross vault. At the present time the vault converted into a space for exhibitions, concerts and meetings. In summer, in the crypt is a cozy cafe.