Colloids are heterogeneous systems formed by small particles dispersed in a continuous medium, such as proteins in water (milk) or fine particles suspended in the air (smoke). Over the last decades, colloids became ‘nanoparticles’ and, as such, contributed to the nanoscience revolution, particularly in the fields of responsive fluids, nanomedicine, imaging…. Interfaces were not left behind! Currently, scientists exploit (nano)interfacial phenomena in solar cells, catalysis, oil recovery, self-cleaning windows, etc. These advances owe much to the insight of Irwin Langmuir who published his seminal article on the liquid interface just a hundred years agobased on his observation of the spreading of oil on water….