The Villa Diodati is a mansion in the village of Cologny near Lake Geneva in Switzerland, notable because Lord Byron rented it and stayed there with Dr. John Polidori in the summer of 1816. Mary Shelley, Percy Bysshe Shelley, and Mary’s stepsister Claire Clairmont, who had rented a house nearby, were frequent visitors. Because of poor weather, in June 1816 the group famously spent three days together inside the house creating stories to tell each other, two of which were developed into landmark works of the Gothic horror genre: Frankenstein by Mary Shelley and The Vampyre, the first modern vampire story, by Polidori.

Cologny is a municipality in the Canton of Geneva, Switzerland.