Context view, looking southeast towards the Eiffel Tower, showing the Pont d'Iena; The 300 m iron tower that became the architectural centrepiece for the Exposition Universelle in Paris of 1889 was probably first conceived by Eiffel's young assistant, the Swiss engineer Maurice Koechlin (1856-1946). Without Eiffel's experience, influence and initiative, however, the tower would certainly never have been built. Although based on Eiffel's earlier viaduct pier designs, this tower required much more complicated calculations and construction methods. The vast number of working drawings, prepared under Koechlin's supervision, were extremely precise, making it possible to assemble the prefabricated components on site with virtually no modification...