The boat passage
Several hundred metres along a flooded tunnel the lead miners cut 250 years ago, with a roof low enough to make you duck.
You do not walk into this cave; you row into it. A steep flight of 106 steps (good handrails) drops you onto a small jetty beside a flooded tunnel that lead miners blasted and chiselled through the limestone in the 1770s, and from there a guide takes a boat of about twenty people along a narrow, low-roofed passage some 200 metres beneath the hill. That is the whole point of Speedwell and what sets it apart from Castleton's other three show caves: they are visited on foot, this one on water. The venture was a financial disaster. The canal swallowed a fortune, produced hardly any lead worth the name, and the mine was abandoned by 1790, at which point it simply carried on as a curiosity for visitors, a tourist attraction before tourism properly existed. The tunnel ends in a natural cathedral-like chamber called the Bottomless Pit: an underground lake with a waterfall dropping into it from some twenty metres above, into which, the guides will tell you, the miners tipped tonnes of spoil without the water level ever rising. The story is surely exaggerated, but standing at the edge in the half-dark you find yourself believing it. Tours last 40 to 65 minutes depending on the season and the cave holds a steady 8 to 9 degrees, summer and winter, so a jacket is essential even in August. It is hard going for anyone who struggles with stairs and impossible for pushchairs and wheelchairs; children under five go free provided they sit on a parent's knee in the boat. Facilities above ground are modest: toilets that need a 50p token from the gift shop, and a small kiosk. The cavern sits at the foot of Winnats Pass, a dramatic limestone gorge that has been the only road west out of Castleton since the Mam Tor road collapsed in 1979, and the drive through it is worth the trip in itself. It is one kilometre west of Castleton, about 40 minutes by car from Sheffield and roughly an hour from Manchester. The car park opposite the entrance is paid (3 pounds for an hour, 6 for two) and enforced by number-plate cameras, so do not overstay. Booking online saves 1.50 pounds an adult and a pound a child, and guarantees a seat during the summer school holidays, when boats fill early.
Several hundred metres along a flooded tunnel the lead miners cut 250 years ago, with a roof low enough to make you duck.
An underground lake in a dim limestone chamber with a waterfall falling some twenty metres into it, and the legend of the spoil that never raised the water.
A spectacular limestone gorge that starts at the cave door; drive or walk it before or after your tour.
Winnats Pass, Castleton, Hope Valley S33 8WA
Speedwell is the more exciting thanks to the boat, and it is the one children remember, but there are 106 steps and a cramped boat that only suits under-fives on a parent's knee. Peak Cavern is a walking tour on mostly level ground with a colossal entrance, so it is the easier choice for a family with a baby or a grandparent. With time for only one, pick Speedwell; doing both takes about three hours and 49 pounds per adult at the door, a little less booked online, and there is no joint ticket.
Yes, it runs daily all year except Christmas Day, Boxing Day and New Year's Day, with the last tour at 15:00 in winter. Rain does not spoil the visit since the temperature underground never changes; it is one of the Peak District's best wet-weather refuges. The one exception is that very heavy rain can raise the canal and close the cave for a day or two, so check the website the morning you go.