Apart from its exceptional intrinsic value and the artistic masterpieces it contains, Cologne Cathedral bears witness to the strength and endurance of European Christianity. Criterion (ii): Constructed over more than six centuries Cologne Cathedral marks the zenith of cathedral architecture and at the same time its culmination. Criterion (iv): Cologne Cathedral is a powerful testimony to the strength and persistence of Christian belief in medieval and modern Europe. Form and design, use and function of Cologne Cathedral have remained unchanged during the centuries of construction. In this respect, Cologne Cathedral may be considered to be sui generis and hence its authenticity is absolute.