Euromast is an observation tower in Rotterdam, designed by Hugh Maaskant. It was specially built for the 1960 Floriade. The tower is a concrete structure with an internal diameter of 9 meters and a wall thickness of 30 cm. For stability it is built on a concrete block of 1,900,000 kg so that the centre of gravity is below ground. It has a “crow’s nest” observation platform and a restaurant. Euromast is a member of the World Federation of Great Towers.