Copenhagen harbor became more and more polluted as the industrialization of the 1800s gained traction. The amount of sewage in the water made swimmers ill and led to a ban on swimming in the harbor in the 1950s.

Then, in the 1990s, over DKK 1 billion was invested in new sewer systems.

Today, when the sewers are almost full, dirty rainwater and sewage are funneled into underground basins. Once there is room in the sewers again, the water can be transported to the wastewater treatment plant.

The improved water quality meant the city’s first harbor swimming pool could open in 2002. Today there are more than 16 places to swim in Copenhagen harbor.