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 and a wall thickness of . For stability it is built on a concrete block of so that the centre of gravity is below ground. It has a "crow's nest" observation platform above ground and a restaurant. Originally in height it was the tallest building in Rotterdam. It lost this position to the high-rise of  Erasmus MC () which was completed in 1968, but regained it when the Space Tower was added to the top of the building in 1970, giving an additional . Euromast is the highest building of the Netherlands, it is also a member of the World Federation of Great Towers. In 2008 and 2009, the tower hosted an extreme sports event which featured BASE jumping.