There is a lot to learn about a society from its buildings, especially if you know what they are used for. For example, find the largest and most decorated buildings (not meaning just decoration, but things like enormous windows, big halls, dramatic stairways, no smaller buildings near them). Are they:
- for religious activities?
- for watching people compete or fight, possibly be hurt or die?
- for shopping?
- for watching people sing, dance, perform a play?
- for generating electricity?
- for processing sewage?
- for making stuff (eg a car factory?)
- for educating people?
- for making the laws of the country?
- for judging crimes?
Also look at the features of these important buildings compared to the same buildings elsewhere or at other times. For example, most castles in England were clearly defensive buildings, with thick walls, arrow slits, drawbridges etc. The chateaux of the Loire Valley are enormous buildings, but are basically just houses: if they have moats they tend to be a "water feature" more than a defense mechanism. They don't have arrow slits, or places for an army to gather before a battle. They have tons of doors and their great rooms are for dancing, not for the village to huddle together during a siege. All of this is obvious from the building itself, and tells you a lot about what life was like at that time in that place.
Also look at the large but non decorated buildings. Are they for living in? Working in? What happens a LOT (so you need big buildings) but isn't considered very important (so they're really nothing special)?
You can also look at the arrangement of buildings. Is everything centred around that big church or mall or stadium? Can you see it from everywhere else? Did the city grow from the waterfront back towards the hills? What is on the edge of town and what is in the heart of everywhere? Are there different parts of town for different things?
Then examine at the building level. Are activities mixed that other societies separate? For example, people once used to keep their animals in the same buildings as themselves. In some places, people work at home or live at work, and in others such activities never mix. In some houses there is a schoolroom to educate the children of the house: in others the children go to a completely different place to learn. How many bedrooms are there? How many bathrooms? In an office building, are there gender-segregated bathrooms? In an office building, are there large meeting rooms? Are some offices larger than others? Is there a room for recreation? Is there an attached daycare? Is there a place to put your bicycle? Does a residential apartment have a balcony? Is it for sitting on with a glass of wine, or for growing tomatoes?
Now all of this is harder when it's historical and you don't know what people did in the buildings or what the rooms were for. But you find stuff in the ruins, and maybe you have art showing things in use, and you can piece together a lot that way.
While it may not come up in general conversation, studying buildings from long ago is one of the ways your history textbook came to know the things it states to you so calmly as fact. Did most families own slaves? Were home vegetable gardens an important source of food? Did every village have a market square? Were the buildings near the docks mostly businesses with no-one living there? All that information is likely to have been pieced together by studying buildings. They just don't tell you in the book how they come to know these facts, instead concentrating on telling you the facts.