Euromast
 Euromast is an observation tower in Rotterdam Netherlands designed by Hugh Maaskant constructed between 1958 and 1960. It was specially built for the 1960 Floriade and is a listed monument since 2010. The tower is a concrete structure with an internal diameter of 9 m (30 ft) and a wall thickness of 30 cm (12 in). For stability it is built on a concrete block of 1900000 kg (4200000 lb) so that the centre of gravity is below ground.