World, publicado con notable éxito en 2002, y con sucesivas ediciones y traducciones. Su autor, Gavin Menzies, construye un relato en torno al hecho alternativo de que no fue Elcano, sino una expedición china la que un siglo antes de la expedición española completara la primera circunnavegación del globo. Metodología. Se propone el caso de estudio del libro de Menzies. Para ello, la pregunta de estudio de partida es: ¿cómo y por qué el relato de una falsa primera vuelta al mundo es construida y diseminada? ¿Cómo un caso de fake history es contrarrestado? Para responder a dichas preguntas, analizamos múltiples fuentes de evidencia, tales como los discursos y documentación tanto online como offline en torno al caso. Asimismo, se construye un modelo de análisis desde el paradigma contemporáneo de las noticias falsas y la posverdad. Resultados. El estudio subraya que el impacto del libro arranca justo con el inicio de la llamada era de la posverdad, y que su incremento coincide con el momento propicio de la posverdad en el mundo digital. Una vez analizadas las evidencias, se verifica cómo unos "hechos alternativos" históricos como estos son creados, trasmitidos y mantenidos en el tiempo, y cómo intereses comerciales y propagandísticos pueden estar detrás de algo así. [ENG] Introduction. 500 years ago, Magallanes undertook a trip that would end up being, in the hands of Juan Sebastián Elcano, the first round the world. But, surprising as it may seem, not everyone accepts this historical truth. Such is the case of the book 1421: The Year China Discovered the World, published with remarkable success in 2002, and with successive editions and translations. Its author, Gavin Menzies, constructs a story about this alternative fact: a Chinese expedition completed the first globe circumnavigation a century before the Spanish expedition. Methodology. A case study research of Menzies' book and its impact is proposed. To do this, we will start with the study question: How and why a false story around a historical event is nowadays constructed and disseminated? And how this fake history is counteracted? To do that, we will analyze multiple sources of evidence such as discourses and documentation in online environment. Results. The study underlines that the impact of the book starts right during the beginning of the so-called post-truth era, and it increases coinciding with these propitious moments for the propagation of fake news and fake history. Once analyzed the evidences, it is verified how historical alternative facts like these are created, transmitted, and maintained in time, and how commercials and also propagandistic interests can be behind of something like this. Conclusions. Not even the well-known first round to the world by Magallanes-Elcano is safe from the misinformation in the current era of post-truth. It is therefore important to remember once again the need to teach and spread historical truths in a rigorous, but also attractive and seductive way. At least as much as the fake history usually does. The disruptiv...