Scandinavia's Nordic Hi-Fi Magazine and the LG's curved OLED-TV are both the same width: 4 millimeters.
So M&C Saatchi created "The World's Slimmest Ad" by advertising on the spine of Nordic Hi-FI Magazine. Nice media placement.
But World's Slimmest? Puhlease. Mini ran ads in the gutters of magazines like ten years ago, dudes.