Castles remain highly popular attractions: in 2018 nearly 2.9 million people visited the Tower of London, 2.1 million visited Edinburgh Castle, 466,000 visited Leeds Castle and 365,000 visited Dover Castle. Ireland, which for many years had not exploited the tourist potential of its castle heritage, began to encourage more tourists in the 1960s and 1970s and Irish castles are now a core part of the Irish tourist industry. British and Irish castles are today also closely linked to the international film industry, with tourist visits to castles now often involving not simply a visit to a historic site, but also a visit to the location of a popular film.