Torre Abbey Gardens Torquay

Built in 1196, this impressive abbey is a setting for arts and cultural events, but it's the wonderful gardens that are of most interest – particularly to Agatha Christie fans. The Potent Plant plot features species which can be used to make the poisons that feature in the crime writer's novels. Particularly deadly are the prunus family (its fruit stones can be used to make one of Christie's favourites: cyanide), foxglove and monkshood.