Issues regarding occupancy comfort in vibration-sensitive structures are the motivation of this study concerning wind-induced vibrations in the European Court Towers in Luxembourg. In one of the two identical towers tuned liquid dampers (TLD) have been installed. Recent studies investigate the changes in the dynamic behavior of the artificially damped tower, before and after the activation of TLD's. This paper widens these investigations and exploits the benefit of having two similar full-scale structures with dissimilar damping characteristics. The main subject of interest in the investigation is the difference in vibration level as well as the modal damping ratios of the towers at various excitation levels. The experimental measurements that form the basis of this paper were conducted during a period of two weeks in the fall of 2010.