Stretching from the Welsh midlands almost to its northern coast, Snowdonia National Park covers a vast swath of North Wales. The park consists of 840 square miles of rocky mountains, valleys clothed in oak woods, moorlands, lakes, and rivers, all guaranteeing natural beauty and, to a varying extent, solitude. Its most famous attraction, by far, is the towering peak of Mt. Snowdon. The view from the top is jaw-dropping: to the northwest you can see the Menai Strait and Anglesey; to the south, Harlech Castle and the Cadair Idris mountain range. To the southwest, on an exceedingly clear day, you can make out the distant peaks of Ireland's Wicklow Mountains. There are six different walking paths to the top, but a far less punishing way is via the Snowdon Mountain Railway, in nearby Llanberis.
Perched at the top of Snowdon is Hafod Eryri, an eco-friendly replacement for the previous visitor center (once described by Prince Charles as "the highest slum in Wales"). The granite-roof building, which blends beautifully into the rocky landscape, has a café and exhibitions about the mountain, its ecology, and its history. If you're planning to make the ascent, the visitor center in Betws-y-Coed is the best place to stop for information.
Royal Oak Stables, Station Rd., Betws-y-Coed, LL24 0AH, Wales