Coetan Arthur Dolmen

A 5,000-year-old stone tomb in the middle of Pembrokeshire farmland - that's Coetan Arthur, and it's the sort of place that stops you dead when you round the corner. The dolmen sits in a field near Haverfordwest, a massive capstone balanced on uprights, looking like something out of folklore. Which, fair enough, it basically is - legend claims King Arthur slept here, though archaeologists are rather more sober about the whole thing.

You can wander right up to it, no gate, no ticket office, just you and four and a half millennia of Welsh history. The structure itself is modest compared to some megalithic sites, but there's something about standing beside a stone that's been here since the Bronze Age that puts the phone down pretty quickly. Bring kids and they'll actually engage - it's real, it's old, and you can touch it.

Allow 20 minutes maximum unless you're a proper archaeology type, in which case you'll want time to walk the perimeter and think about Neolithic burial practices. Free, obviously. The surrounding countryside is decent for a stroll, rolling fields with views back towards Haverfordwest. Worth combining with a visit to one of the nearby caravan parks - Pencarnan Farm or Lleithyr are both within a mile or so - if you're basing yourself in the area for a few days. Don't expect visitor facilities or explanatory boards. This is old Wales in its purest form: rough, unadorned, and all the better for it.