Beautiful wooded valley with 19th-century Gibson Mill at its heart.
A beauty spot of the South Pennines with more than 160 hectares (400 acres) of unspoilt woodland.
As well as being the home of the northern hairy wood ant, there are tumbling streams, glorious waterfalls and stacks of millstone grit, all crisscrossed by more than 15 miles (24km) of footpaths.
At its heart is Gibson Mill, a family-oriented visitor centre, telling the history of the valley over the past 200 years, with interactive displays, dressing up, dancing and exhibitions. Having no link to the national grid, the mill is unique in the UK and is the Trust's flagship sustainable building.