Kostanjevica na Krki is the smallest and at the same time the oldest city in Dolenjska. The old city kernel was developed in the artificially made island. It is also dubbed as the Venice of Dolenjska. The city was flooded several times because of its position in the flat land. The floods are not so frequent since they put in order the regulation work in Krka River. In the year 1249 is first mentioned as the square and in the year 1252 as the city. The important rule was playing the duke family Spanheim. The development of the city stopped in the second half of the 14th century. Houses in the old part of the city are arranged in two consucetive streets. One of the street is named Ulica talcev (Veliki plac) and another one is Oražnova ulica (Mali plac). In the island is the most important Church of the Saint Jakob. In the basis the church is built in Romanic Style, but it was later changed to Baroque Style. Probably was built in the fourth part of the 13th century to protect the city. Gothic tower has rococo roof. Worth seeing is also the Church of Saint Miklavz, manor house from the 15 th century, old tollhouse from the 17th century, Bartolli house from the beginning of the 20 th century, which is famous by its ornaments in the facade and others.
The famous people in Kostanjevica are: Lenart Pachenecker (died 1581), Cistercian, author of the first Slovenian Catholic book, Ivan Orazen, doctor and Maecenas of the Faculty of medicine in Ljubljana, Joze Gorjup, painter and sculptor, Tone Kralj, painter and graphic, Joze Likar and many others. The central part of Kostanjevica is in the Kambic Square. They have a bank, hospital, shops, police station and elementary school, which is from the year 1789. The most important cultural monument outside the island is former Cistercian Monastery. The local people also calls it Kloster or Castle. The Church of the Virgin Mary and the cloisters are the oldest part of the monastery. In the monastery is the Gallery of Bozidar Jakac, which was established in the year 1974. The castle grounds are used to exhibit over 100 large wooden sculptures from Forma Viva, an international exhibition once held in several places in Slovenia from 1961 to 1988 whereby sculptors worked with materials assosiated with the area. Here it was oak, in Portoroz stone, iron at Ravne in Koroska and shudder concrete in Maribor. In the future Forma Viva will be organized every two years.