I just arrived in the beautiful city of Amsterdam, Netherlands. In the early seventeenth century, when immigration was at a peak, a comprehensive plan for the city’s expansion was developed with four concentric half-circles of canals emerging at the main waterfront (seen at the left in this Overview). In the centuries since, the canals have been used for defense, water management, and transport. They remain a hallmark of the city to this day. Hallo Amsterdam!