With National Park and designated Sites of Special Scientific Interest status, the Norfolk Broads is an important area for wildlife and conservation. In total, there are over 200 km (125 mi) of navigable waterways linking the broads, man-made by peat-diggers from Medieval times onwards. The Broads, a small part of which lie within Suffolk, attract ramblers, photographers and artists and particularly bird-watchers. Fishing is also popular with around 25 species of freshwater fish. Many parts of the Park can only be explored by water: boats and other craft are available for hire throughout and a strict speed limit applies, reinforcing the serenity of the experience.