How did the outward appearance of European cities change in the 17th-18th centuries? What has survived in them from the Middle Ages?

In the XVII-XVIII centuries. during the development of new districts, slums were demolished, wide streets were laid and squares were broken up. Frequent fires forced the townspeople to build houses of stone and brick. Glass was increasingly being inserted into the windows. Roofs covered with tiles began to come into fashion.
Ancient powerful walls have been preserved in European cities from the Middle Ages.

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