Snowdonia National Park

Two thousand square kilometres of proper mountain scenery, and Snowdonia doesn't apologize for any of it. This is the big one in North Wales - jagged peaks, glacial valleys, and enough slate-grey weather to make you wonder why you didn't pack another jumper. You're looking at Snowdon itself (the one everyone climbs), but also Cader Idris, the Glyderau range, and stretches of coastline that suddenly materialize when the mist clears. Real walkers spend weeks here; families might tackle an afternoon ridge walk from Betws-y-Coed and call it done.

The park works for everyone eventually. Serious hikers get their teeth into multi-day treks. Kids manage the slate mines and mountain railways without needing their legs to work too hard. Lake walkers potter around Llyn Tegid. There's a steam railway that runs through the middle of it all, which does something peculiar to even the most jaded adults.

Free to enter, though individual attractions - the mountain railway, the mines - charge separately. Timing depends entirely on what you're doing. A valley walk takes two to three hours. Snowdon's full summit push is five to six hours, and that's without dawdling. Conwy Valley Touring Park sits just outside at Betws-y-Coed, making it a sensible base for a week's worth of exploring without moving the caravan.

Go in late May or early September. Summer's rammed. Winter's serious business unless you know what you're doing.