Historic center of Prague is the place in Czech Republic, which is visited most often. The Charles Bridge and the St. Vitus Cathedral are the most characteristic objects in the center. The bridge, which is over 500 meters long, is the oldest stone bridge in the world. It was built in 14th century on the Vltava River during the reign of emperor Charles IV (hence the name). The St. Vitus Cathedral (the full name of the cathedral: St. Vitus, St. Wenceslaus and St. Adalbert Cathedral) is the residence of the Prague archbishopric, located in Hradčany. The cathedral was built in Gothic style. Today, it is the place where important pieces of art and the Czech royal insignia are kept.