J.B. Bakema. Observation tower ‘Euromast’, Rotterdam, 1958. NAi Collection / MAQV 1144 Bakema designed the 125-meter observation tower on the occasion of the first international horticulture exhibition "Floriade", (Rotterdam, 1960). He based his idea for the structure on the Wolkenbügel projects by El Lissitzky in the 1920s. The municipal council wanted to erect a structure that reflected the pride of the city of Rotterdam. Bakema's design was never realized though.
Arche Nebra / Holzer Kobler Architekturen - Nebra Observation Tower by Holzer Kobler Architekturen // Divided by a vertical crevice extending over its full height to mark the summer solstice, functioning as a solar calendar.