Civil engineering is one of the oldest and broadest engineering professions. It focuses on the infrastructure necessary to support a civilized society. The Roman aqueducts, the great European cathedrals, and the earliest metal bridges were built by highly skilled forerunners of the modern civil engineer. These craftsmen of old relied on their intuition, trade skills, and experience-based design rules, or heuristics, derived from years of trial and error experiments but rarely passed on to the next generation.