In 2026, The Nightmare Realm celebrates its 17th year, having commenced in Ireland back in 2009. Lady Sundown, of Sundown Manor (Image: The Nightmare Realm)The Halloween Town is structured as far more than just a passageway between two attractions. READ MORE:The founders of The Nightmare Realm, Karl and Sylvia O'Connor, explained their excitement about the London venture. The Nightmare Realm will operate on selective dates in Greenwich, London from October 9 to November 1, with increases in visitor numbers expected around the weekends and Halloween week. A multiple winner of Best Halloween Event in Europe at the ScareTOUR Awards, The Nightmare Realm has proved itself as an impressive horror experience.