During renovations to the Notting Hill Gate tube station, Mikey Ashworth of the London Underground found a treasure trove of old posters on the walls of an elevator passageway, which had been sealed off during construction in the 1950s. Check out these vintage advertisements for toothpaste, movies and exhibitions—pretty spectacular discovery! And should any modern era posters be sealed off in this current round of construction, we bequeath our own graphic masterpiece to future generations... the ubiquitous Momma Mia ad. See the complete collection. (All photos credit of London Underground)