the area, eventually donating her many properties to the National Trust. Shipbuilding later replaced iron and steel as Low Furness's main industry, and Barrow's shipyards became the largest in England. In particular, submarine development became a specialty of the town, with the Royal Navy's first submarines built there. During the wars this allowed Furness to escape many of the economic problems that other areas suffered, due to the constant work provided by the military. After World War II demand for ships and submarines remained high, while the development of the Lake District National Park further fostered tourism. Attractions such as the Lakeside and Haverthwaite Railway, steamers on Windermere and Coniston Water, and fell walking, caused parts of Furness to become dependent on the tourist trade. In the early 1990s, the decline of shipbuilding led to mass redundancies in the area. The shipyard's employment figures fell from 20,000 to 3,000 in a 20-year period. However, the shipyard at Barrow remains England's busiest and the only nuclear submarine facility in the country. Tourism has increased even more, with the Aquarium of the Lakes and South Lakes Safari Zoo among the newer attractions. Transport has become an increasingly controversial issue, with conservation groups and local business clashing over the need for improvements to the A590 trunk road, the main link to the M6 Motorway. Proposals for a road bridge over Morecambe Bay have appeared, but are yet to progress beyond the planning stages. Administration Furness formed the greater part of the North Lonsdale exclave of the historic county of Lancashire, which bordered Cumberland to the northwest and Westmorland to the northeast (the point where the three counties met is marked by the Three Shire Stone at the head of the Duddon). North Lonsdale is also called "Lancashire North of the Sands". In 1974, North Lonsdale – along with Cumberland, Westmorland, and part of the West Riding of Yorkshire (around Sedbergh) – became part of the new administrative county of Cumbria. At the district level, it now consists of the borough of Barrow and part of South Lakeland. From April 2023, Furness will form part of the new unitary council area of Westmorland and Furness, which will replace Cumbria County Council and the districts of Barrow and South Lakeland, all of which will be abolished. Low Furness and the western part of High Furness are in the Barrow and Furness parliamentary constituency, while eastern