Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Speyer Cathedral' has mentioned 'UNESCO World Heritage List' in the following places:
Occurrence Sentence Text Source
In 1981, the cathedral was added to the UNESCO World Heritage List of culturally important sites as "a major monument of Romanesque art in the German Empire".
In April 1981, Speyer Cathedral was added to the UNESCO World Heritage List of culturally important sites.