Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and constructing buildings or other structures. The term comes from Latin architectura; from Ancient Greek ἀρχιτέκτων (arkhitéktōn) 'architect'; from ἀρχι- (arkhi-) 'chief' and τέκτων (téktōn) 'creator'. Architectural works, in the material form of buildings, are often perceived as cultural symbols and as works of art. Historical civilizations are often identified with their surviving architectural achievements.
The practice, which began in the prehistoric era, has been used as a way of expressing culture by civilizations on all seven continents. For this reason, architecture is considered to be a form of art. Texts on architecture have been written since ancient times. The earliest surviving text on architectural theories is the 1st century BC treatise De architectura by the Roman architect Vitruvius, according to whom a good building embodies firmitas, utilitas, and venustas (durability, utility, and beauty). Centuries later, Leon Battista Alberti developed his ideas further, seeing beauty as an objective quality of buildings to be found in their proportions. In the 19th century, Louis Sullivan declared that "form follows function". "Function" began to replace the classical "utility" and was understood to include not only practical but also aesthetic, psychological, and cultural dimensions. The idea of sustainable architecture was introduced in the late 20th century.
