Artificial hills or mounds were once the weapon of choice in the centuries-old battle to protect the Netherlands against water. Gradually they were replaced by a countrywide network of dykes.

But half of the Netherlands lies under sea level and it’s feared the dykes won’t be able to provide enough protection against rising sea levels or flooding resulting from climate change.

So water engineers are turning back to the old methods and have begun work on a new mound in the south of the Netherlands.