In its centuries of growth Paris has for the most part retained the circular shape of the early city. Its boundaries have spread outward to engulf the surrounding towns (bourgs), usually built around monasteries or churches and often the site of a market. From the mid-14th to the mid-16th century, the city’s growth was mainly eastward; since then it has been westward. It comprises 20 arrondissements (municipal districts), each of which has its own mayor, town hall, and particular features.
