Architecture is the art and science of designing buildings, bridges, and other structures. It aims to satisfy aesthetic requirements while ensuring structural integrity and functionality. Architects specialize in designing structures. Key architectural developments include the post-and-lintel method, classical orders like columns and entablatures, arches, vaults, domes, flying buttresses, and modern materials like concrete, glass, and iron used in landmarks such as the Parthenon, Roman aqueducts and baths, Gothic cathedrals, and the Eiffel Tower.