Snowdon is the highest mountain in Wales, at an elevation of 1,085 metres above sea level, and the highest point in the British Isles outside the Scottish Highlands. It is located in Snowdonia National Park in Gwynedd. It is the busiest mountain in the United Kingdom and the third most visited attraction in Wales, with 582,000 people visiting annually. It is designated as a national nature reserve for its rare flora and fauna.
The rocks that form Snowdon were produced by volcanoes in the Ordovician period, and the massif has been extensively sculpted by glaciation, forming the pyramidal peak of Snowdon and the arêtes of Crib Goch and Y Lliwedd. The cliff faces on Snowdon, including Clogwyn Du'r Arddu, are significant for rock climbing, and the mountain was used by Edmund Hillary in training for the 1953 ascent of Mount Everest.
The summit can be reached by a number of paths, and by the Snowdon Mountain Railway, a rack railway opened in 1896 which carries passengers the 4.7 miles from Llanberis to the summit station. The summit also houses a cafe called Hafod Eryri, open only when the railway is operating; it opened in 2009 to replace one built in the 1930s.