text: The north tower , the Tour Saint-Romain , has the sober simplicity of the cathedral 's early Gothic beginnings in the 12th century , while the taller , more elaborate south tower , the Tour de Beurre , is Flamboyant Gothic of the 15th century .
  
  ###
  
  Both the Tour de Beurre and Tour Saint-Romain are modern churches in the brutalist architectural style .