Location: Gwynedd, North Wales. Snowdonia National Park extends into Meirionnydd Date completed: formed during the Ordovician period, c. 458 million years ago. Designers/builders: natural feature Function: National Park

Snowdon, the highest mountain in Wales at 3,560 ft (1,085 m), has a special place in Welsh history. The great Welsh ruler, Llywelyn ap Gruffud, used the title "Prince of Wales and Lord of Snowdonia" (in Welsh, "Tywysog Cymru ac Arglwydd Eryri"). Eryri is the Welsh name for the mountain, which some say is derived from "eryr" (eagle) but more probably simply meant "highlands". The name "Snowdonia" originally applied to an upland area surrounding the mountain and its satellites, the Glyderau, the Carneddau and the Moel Siabod group. Today it is more usually applied to the Snowdonia National Park, which is an area of 827 sq m (2140 sq km), almost twice the size of Snowdonia, and was designated as the third National Park in Britain in 1951. Unusually the park has a "hole" in the middle around the town of Blaenau Ffestiniog. This was done to make it easier for industry to set up in the area, following the closure of the slate quarries. In fact, the slate quarries and the narrow gauge railways that served them are an important part of the charm of the area that drew visitors to spend six millions days in Snowdonia last year. Railways that once carried slate from the quarries to the coast now carry thousands of visitors through the magnificent Snowdonia scenery. Like the Talyllyn railway, the world's first preserved railway, rescued and restored by an army of enthusiastic volunteers, which steams through the southern mountains of Snowdonia National Park. It's said to have inspired Thomas the Tank Engine. The Ffestiniog railway runs through 13½ miles of breathtaking scenery from Portmadog to Blaenau Ffestiniog. Perhaps the most spectacular is the Snowdon Mountain Railway that takes you on a four miles journey to the summit of Snowdon. Or you can walk or climb, like thousands of the more active visitors who come to take advantage of some of the most rewarding walking and climbing country in Britain. The Snowdonia National Park also includes 37 miles of beautiful coastline with seaside resorts and charming villages.