National Showcaves Centre for Wales

Three underground cave systems sit beneath the Brecon Beacons, and the National Showcaves Centre pulls them together into one proper expedition. You're walking through Dan-yr-Ogof, Cathedral Cave, and Bone Cave - each one revealing something different. Dan-yr-Ogof is the star turn, a massive cavern system with an underground lake that catches the light like something from another world. Cathedral Cave lives up to its name: the acoustics are genuinely cathedral-like, and the sheer scale of the chamber stops you mid-stride. Bone Cave is smaller, more intimate, and historically significant - human remains from thousands of years ago were found here.

Allow at least three hours, though you could easily spend half a day if you're thorough. The walks are relatively gentle but involve proper climbing and navigating uneven ground, so it's not for anyone with mobility issues. Families with children from about eight upwards tend to cope well - younger kids might struggle with the darkness or the tight spots. The temperature drops noticeably underground, so bring a jumper even in summer.

It's a paid attraction, and worth every penny if cave systems fascinate you. The guides know their stuff and won't bore you with scripted patter. From here, you're perfectly positioned for the Brecon Beacons proper - Brecon Beacons Camping & Caravan Park sits just 0.3 miles away, making it a sensible base for a week exploring the hills and valleys. Aber Glamping and Four Falls Glamping offer more upmarket stays if you want a bit of comfort after crawling through limestone all day. The nearest proper town is Swansea, but honestly, you don't need to go that far.