Córdoba was once the most important city in Europe. It was the centre of the medieval Caliphate of Córdoba and capital of the western Islamic Empire. It reached its peak in the 10th century when it rivalled Baghdad and Constantinople as one of the great cities of the World. Its greatest surviving monument to the city’s magnificent past is its Grand Mosque – the Mezquita. Work on the mosque actually started in 786 when it was built on the site of an old Visigothic church. However, it was enlarged three times before reaching its present size in 987 when it became the largest sacred building in the Islamic world. And big it most certainly is - so massive that a Gothic cathedral was built inside the mosque - and a few chapels!