St. Peter and Paul's Cathedral was designed by Carlo Rossi and completed in 1841. It is the Catholic Cathedral of Tallinn. During the period of Swedish rule (1561-1721) Catholicism was banned. When Sweden ceded Estonia to the Russian Empire at the end of the Great Northern War, the new authorities introduced religious freedom. In 1799, the Catholic parish grew and took over the use of the former refectory of St. Catherine's Monastery, which had remained closed since the ban. The refectory was used as a place of worship and is located on the site of the present church. In 1841, as the place of worship had become too small, a new church was designed by Carlo Rossi.
St. Nicholas' Church was founded in 1230 as the centre of a settlement of German merchants from Gotland. The church was completely rebuilt in 1405-1420 when a new choir was built and the then long building was rebuilt according to the principles of the basilica. From 1486 to 1493, the Matthew Chapel (14th century) was rebuilt as Anthony's Chapel. The new tower of the reconstructed church was completed in 1515. The west tower of the church was rebuilt in 1682-1696 and a new baroque bell tower was built. After its restoration after the Second World War (1953-1981), the church became an art museum and a concert hall.
St. Olaf's Church was founded in the 12th century by the Scandinavians who occupied the city at that time and was named after King Olaf II of Norway. The building has been preserved as it was rebuilt in the early 15th and 16th centuries. The church also had to be partially rebuilt after fires in 1625 and 1820. The tower, which was destroyed in the fire of 1820, was restored in 1840, and at the same time, the neo-gothic interior of the church was completed.