Malham Tarn lies 377 metres up on the limestone moor above Malham, England's highest lime-rich lake and the heart of a National Trust estate of upland farms, wetland and pasture crossed by six miles of the Pennine Way. A boardwalk weaves through the tarn's National Nature Reserve and its wildflowers, including yellow globeflower and pink and purple orchids. Roe deer are often seen around Tarn House, the former hunting lodge where a visit in 1858 inspired Charles Kingsley to write The Water-Babies. The Trust's 2-mile National Nature Reserve walk starts from Waterhouses car park, and its 4.5-mile upland farm circular from Watersinks passes the old smelt mill chimney. Dogs on leads are welcome across most of the estate, but only assistance dogs may use the reserve boardwalk. Nobody may swim or paddle in the tarn. Reviewers rate it for photography, water birds and peace and quiet among the sheep. Tips from visitors: bring waterproofs and sturdy boots, as the ground is rough and the weather changeable. A Tramper mobility scooter can be booked in advance.