It is always worth walking around a building before entering, since this can tell you a lot about its form and what its builders wanted to achieve. On most buildings every fagade is different. The shape and texture of each of them can be surprising and the back often looks very different from the front where the entrance is. Every part of a building's exterior.
24 TOWERS A tall, late-medieval building, such as the Belem Tower (left), has a series of protrusions that make its solid form more complex and decorative. By contrast, the classic skyscraper form is a tall tower with setbacks creating a tapering effect. Pioneered by the builders of towers such as New York's Chrysler Building (right), this form was adopted for countless other skyscrapers around the world contributes to the overall effect. Both a castle tower and a skyscraper, for example, dominate their site and are designed to make people stop and marvel at the status of the people who had them built. They achieve this effect in different ways. The protruding turrets and balconies of a castle tower create much of its impact; the dramatic effect of a skyscraper is enhanced by its setbacks the way in which the tower is stepped back in stages toward the top. Features such as classical porticos, the design of doorways and window openings, or supporting arches, also add interest. They break up the form, and sometimes, as with the windows on a skyscraper or the rows of buttresses on a medieval cathedral, create a rhythmic repetition that gives the exterior additional visual variety. Such features are all aspects of a building's form and add to its character.
Architects often think of a building as a series of spaces: when designing a new building, they start with the functions that the structure needs to fulfill, design spaces for those functions, and then define the spaces using walls, windows, and roofs. The character of an interior, therefore, varies immensely from one building to another.