Located on the Morava River, the city is the ecclesiastical metropolis and was a historical capital city of Moravia, before having been sacked by the Swedish army during the Thirty Years' War. Today, it is the administrative centre of the Olomouc Region and the sixth largest city in the Czech Republic. The historic city centre is well preserved and is protected by law as urban monument reservation. The Holy Trinity Column was listed as a UNESCO World Heritage Site in 2000 for its quintessential Baroque style and symbolic value.