Spaans Lagoen on the west coast of Aruba is a narrow inner bay of 2,000 meters long and 500 meters wide. The tides have created a special ecosystem: a wetland (wetland). Spanish Lagoen is the only inland bay of One Happy Island and was created as a result of the sea level rise after the last ice age, about 10,000 years ago. Spaans Lagoen is about 70 hectares in size and is part of the  Arikok National Park . Arikok National Park covers 20 percent of Aruba.

Wetlands are areas between rural and wetland areas and have a great biodiversity. The inner bay of Aruba is therefore of great importance for waterfowl and it is also an important nursery for  reef fish  and shellfish. Spaans Lagoen is so unique worldwide that it is part of the Ramsar Convention.