The 900-year-old World Heritage Site triumphed in the inaugural Travellers’ Choice Attractions awards, organised by Trip Advisor.
The towering Norman construction triumphed over Edinburgh’s Camera Obscura and World of Illusions, with its awe-inspiring views of the Scottish capital and York Minster which was third.
Durham Cathedral, which attracts 600,000 visitors a year, was placed 20th in the Europe-wide landmark list, with the Great Cathedral and Mosque, in Cordoba, Spain, top of the list.
The Inca settlement of Machu Picchu, in Peru, took first place in the worldwide poll.
Ruth Robson, head of marketing and events at Durham Cathedral, said: “We are delighted that it is hailed as the UK’s number one landmark building.