Our verdict
One of the genuinely distinctive features in this whole area — a proper geological curiosity rather than just another patch of heath — and popular enough that you won't have it to yourself on a weekend. Steep drops around the rim mean it's worth keeping dogs and children close.
A dramatic 90-metre-wide, 40-metre-deep dry doline (sinkhole) in the forest near Briantspuddle, formed by underground water dissolving the chalk and the ground above collapsing into the cavity. It's named after the 17th-century herbalist Nicholas Culpeper, after a solitary tree at the bottom once looked like a pestle in a giant mortar. Forestry England paths and a car park give easy access, with the wider forest walk continuing towards Affpuddle.