The cage descent
Ninety metres down in the original miners' cage, led by a guide who was one of them.
They hand you a helmet, a lamp and a battery pack that drags at your belt, take away your phone, watch and anything else with a battery in it, and then the same iron cage that once carried the colliers drops you ninety metres into the dark. At the bottom a guide who actually worked the South Wales pits walks you for about an hour through real roadways where coal was cut from 1880 until the mine closed in 1980. Nothing is a replica or a film set, and that is the whole point of the place. Big Pit sits in the town of Blaenavon, roughly fifty kilometres north-east of Cardiff: about an hour by car along the M4 and then the A4042 north through Pontypool, and a car is realistically the only sensible way. Trains reach Abergavenny or Pontypool, but the local bus onward runs infrequently. The town is part of the Blaenavon Industrial Landscape, a UNESCO World Heritage Site, and the view from the car park alone, bare green hills and the shells of old ironworks, explains why. The museum itself is free. The underground tour costs £5 if you buy it on arrival with no fixed time, or £8 for a pre-booked timed ticket, and parking is £5 for the day. In the school summer holidays booking ahead spares you a wait that can stretch, because groups go down in small numbers. The rules are strict: children must be over one metre tall, and the lamp and battery weigh around five kilograms, so this is not for toddlers and pushchairs stay above ground. It is cold and damp below with low roofs in many stretches, so bring a coat and closed shoes even in August. Above ground there is enough for another hour: the old pithead baths now house an exhibition on mining families, there is the winding house, the King Coal gallery on the Welsh coal industry, and a modest coffee shop for drinks, cakes and snacks, with space to picnic. Open daily 09:30-17:00, last entry 16:00, underground tours 10:00-15:30, though tour hours shrink and may be suspended between December and early February, so phone or check the official site before driving up. From Cardiff allow half a day, and it pairs well with the nearby Brecon Beacons.
Ninety metres down in the original miners' cage, led by a guide who was one of them.
About an hour of stooped walking through roadways where coal was actually cut for a century.
The above-ground galleries on mining families give meaning to what you saw below.
Blaenavon, Torfaen NP4 9XP
Anyone under a metre tall cannot go underground, and the five-kilogram lamp is heavy for small children, so the family will end up splitting. With primary-school-age children and older it is well worth it; with toddlers, stay in the city and do the National Museum Cardiff instead.
In July, August and at weekends book the £8 timed ticket: groups are small, walk-up places are limited and the wait can be long. On a weekday outside summer the £5 walk-up ticket is usually fine, especially if you arrive early.