The main attraction of the city, which became his symbol is the Imperial Cathedral. Thanks to its location on an elevated site and monumental size (length 134 meters, width of 33 meters) silhouette of the Cathedral with four towers and two domes visible from afar. This is the largest monument of Romanesque architecture in Germany in 1981 was included in the UNESCO world cultural heritage site by UNESCO.

The construction of the Cathedral began around 1025, during the reign of Conrad II. The Cathedral was consecrated in 1061. In 1041 year was consecrated to his crypt that served as the burial place of emperors and kings for three hundred years. When Henry IV was added vaulted ceilings, towers and apse.

For thousands of years the Cathedral has been restored and supplemented, changed its appearance. The largest catastrophe in the history of the Cathedral took place in 1689, when the soldiers of the French king Louis XIV destroyed it, leaving almost only the walls, and defiled in the Cathedral of burial. In 1772-1784, the Cathedral was renovated and expanded lobby and façade, however, soon again captured and desecrated by the French. In 1846-1853 held a full restoration and decoration of magnificent frescoes on the funds of the Bavarian king Ludwig I.