De Bolder houses the headquarters of the Mammoet ship salvage and rescue company. The aim of the design was to depict the structure as an icon of strength, power and solidity. The building was pre-fabricated on a shipyard and is made of steel with an aluminium cladding. After it was built, it was moved on pontoons along the river and then anchored to its final site. Due to the special contruction techniques used, it was awarded the status of demonstration project, with the emphasis on industrial, flexible and sustainable building techniques.