The Church of Saint Donat was originally the center of the Holy Trinity, which is a precious monument. The church was designed in the style of pre-Romanesque architecture in the early Middle Ages in Croatia, and due to its distinctive shape and ancient design, it became one of the most important religious monuments in Europe. The church was characterized by its circular shape and double ring, with a unique character unlike any of the other churches in the region, and it also contains high stone beams decorated in unique ways. Tourists and pilgrims come to this sacred spot from all over the world, as it is one of the most important churches in the world.