The Au-S interaction is probably the most intensively studied interaction of Au surfaces with nonmetals, as, for example, it plays an important role in An ore formation(1) and controls the structure and dynamics of thiol-based self-assembled monolayers (SAMS).(2-4) Various S-induced surface structures on Au(111) were recently reported for different conditions and predominantly interpreted in terms of a static An surface. Here, we demonstrate that the Au(111) surface exhibits a very dynamic character upon interaction with adsorbed sulfur: large-scale surface restructuring and incorporation of An atoms into a growing 2D AuS phase were observed in situ. These results provide new insight into the Au-S surface chemistry.