Córdoba and Baghdad were similar in that both cities were significant cultural and intellectual centers during the Islamic Golden Age, and they played crucial roles in the development of science, philosophy, and the arts. However, when considering your provided options, the most accurate similarity would be:
Both cities were built on major trade routes.
Both Córdoba, in the Iberian Peninsula, and Baghdad, in present-day Iraq, were strategically located along essential trade routes that facilitated commerce, cultural exchange, and interaction between various civilizations, contributing to their prosperity and growth as important urban centers during their respective periods.