Definition: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Input: The structure of Bern's city centre is largely medieval and has been recognised by UNESCO as a Cultural World Heritage Site. Perhaps its most famous sight is the Zytglogge (Bernese German for "Time Bell"), an elaborate medieval clock tower with moving puppets. It also has an impressive 15th century Gothic cathedral, the Munster, and a 15th-century town hall. Thanks to 6 kilometres (4 miles) of arcades, the old town boasts one of the longest covered shopping promenades in Europe.
Output:
The structure of Bern's city centre is mainly what type of buildings?