Big Pit National Coal Museum
For hundreds of years, South Wales has been famous for its mining industry. Decades of decline—particularly during the 1980s—left only a handful of mines in business. The mines around Blaenavon, a small town 7 miles northeast of Abergavenny, have been designated a UNESCO World Heritage Site, and this fascinating museum is the centerpiece. Ex-miners lead you 300 feet underground into a coal mine. You spend just under an hour examining the old stables, machine rooms, and exposed coalfaces. Afterward you can look around an exhibition housed in the old Pithead Baths, including an extraordinary section on child labor in British mines. Children under 3½ feet tall are not allowed on the underground portion of the tour.