To be inscribed on the World Heritage List, World Heritage properties must be of Outstanding Universal Value and meet at least one of ten selection criteria. The Old City of Bern meets criterion III for its inscription.
Criterion (iii): The Old City of Berne is a positive example of a city that has conserved its medieval urban structure whilst responding, over time, to the increasingly complex functions of a capital city of a modern State.
Integrity: The property comprises all the urban historical structures, with all the stages of its development from the 12th century to the 14th century, including the developments of the 19th century, such as the well-preserved bridges and significant public monuments. It, therefore, retains all the requisite elements to express its outstanding universal value.
Authenticity: Although during the first decades of the 20th century, the safeguarding of the Old City was explicitly concentrated on the appearance of the buildings (facades, roofs), the large majority of the historic buildings representing diverse periods have retained their interior structures, and the overall medieval plan has remained intact. The city today demonstrates a good state of conservation of the buildings and a very dynamic and contemporary urban activity.
You can find further information at www.unesco.org.