During the 17th century, Amsterdam was growing so fast it was practically bursting at the seams. The city experienced her economic, political and cultural Golden Age. An expansion was essential. The city council therefore designed a plan that would make the city five times as large. The canals area, with its 14 km of canals and 80 bridges, is a masterpiece of town planning, hydraulic engineering and architecture. Thanks to the systematic planting of trees along the canals and the establishment of beautiful gardens, a very green city quickly arose. This planned urban expansion served as an example around the world until well into the 19th century. The Amsterdam Canal District has been added to the UNESCO World Heritage list in 2010.