The canals of Amsterdam were added to UNESCO’s World Heritage List in 2010 as an example of town planning that influenced the world for centuries. But when they were first built in the 17th century, they weren’t meant for inspiration – they were critical to the survival of the city. They were in part necessary for the expansion of the urban area. The canals were used to drain away the swamps that once dominated the land and, in the spaces between the new waterways, the building began. The canal system provided another important benefit, though. It gave protection to the city at a time when the Dutch were becoming an important power in the world and making enemies and attracting jealousies.