Shelley travelled through Europe in 1815 along the river Rhine in Germany stopping in Gernsheim, 17 kilometres (11 mi) away from Frankenstein Castle, where two centuries before, an alchemist engaged in experiments. She then journeyed to the region of Geneva, Switzerland, where much of the story takes place. The topic of galvanism and occult ideas were themes of conversation among her companions, particularly her lover and future husband Percy B. Shelley. Mary, Percy and Lord Byron had a competition to see who could write the best horror story. After thinking for days, Shelley dreamt about a scientist who created life and was horrified by what he had made, inspiring the novel.