of Answers Buildings that survive tell us about the way spaces were organised and used, how they were built, with what materials and techniques. For example, we can assess the defence requirements and military preparedness of a city by studying its fortifications. Buildings also tell us about the spread of ideas and cultural influences if we compare them with buildings in other places. They convey ideas which the builders or their patrons wished to project.
They are often suffused with symbols which are a product of their cultural context. These we can understand when we combine information from other sources like literature, inscriptions and popular traditions. Source