St Casimir's Church is located in the city centre of Warsaw. It originally housed a residence, which was transformed into a church and monastery complex between 1688 and 1692. The design of the building was commissioned to the eminent Dutch architect Tylman van Gameren. In addition, the building was supervised by Augustin Locci, court architect to John III Sobieski. The central church, founded on the plan of a Greek cross, has five altars. The central nave was covered by a dome with a lantern and set on a high tambour.
St Mary's Basilica, located in Gdansk, is the third largest brick church in the world. Its distinctive silhouette, accentuated by the massive western bell tower and slender corner turrets, creates a dominant feature in the city skyline. Built between 1346 and 1502, the church is an example of Brick Gothic, a variant of the style in Gothic architecture that became widespread in the countries around the Baltic Sea. The church is built on an irregular Latin cross plan. The exterior of the church is dominated by smooth wall planes with high, sharp-arched windows.