The impressive number of over 150 participants at the brownbag lunch “Double Optimized” on October 10th at the « Schweizer Baumuster-Centrale » speaks volumes. Sustainable and hybrid skyscraper construction is a topic that is of great interest to many planners in the city of Zurich. The three speakers were happy to provide information on the pioneering Tilia Tower© project, which is currently approaching its final height of 85 m in Prilly near Lausanne. Robin Kirschke from Itten+Brechbühl AG gave an overview of the project in terms of urban planning and architecture, described the development from the competition win with 3XN through to execution and provided information on the strategies for achieving the ambitious sustainability goals. Our project engineer Michael Stirnimann then presented the challenging structural design of the project, which he knows inside out thanks to his daily involvement with the buildings static. He vividly explained how various methods were used to limit the CO2 footprint, while a high degree of prefabrication ensured rapid construction progress and cost-effectiveness. Fascinating visual impressions from the current construction process effectively illustrated his presentation.