Amsterdam has various parks, which can be visited to relax or for a walk.
Probably the most famous (and often crowded) of the parks is the Vondelpark, but there are a few others worth visiting. The most noteable one is probably the Westerpark / Westergasfabriek. This has become a large park and festival ground, popular with tourists too.
Children's pond Westerpark
Oeverpark (view to IJdock)