Muenster city of Bonn.
<p>Built in the XI-XIII centuries in the Romanesque style and is one of the most beautiful cathedrals on the Rhine.
Together with the crypt located in the Cathedral, it is one of the first Christian buildings on the banks of this river 
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The city's martyred saints are Cassius and Florentius.
<a href="//commons.wikimedia.org/wiki/User:Vitold_Muratov" title="User:Vitold Muratov">Vitold Muratov</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>