Ben Nevis ??iv??]) is the highest mountain in Scotland, the United Kingdom and the British Isles. The summit is 1,345 metres above sea level and is the highest land in any direction for 459 miles. Ben Nevis stands at the western end of the Grampian Mountains in the Highland region of Lochaber, close to the town of Fort William. The mountain is a popular destination, attracting an estimated 100,000 ascents a year, around three-quarters of which use the Mountain Track from Glen Nevis. The 700-metre cliffs of the north face are among the highest in Scotland, providing classic scrambles and rock climbs of all difficulties for climbers and mountaineers. They are also the principal locations in Scotland for ice climbing. The summit, which is the collapsed dome of an ancient volcano, features the ruins of an observatory which was continuously staffed between 1883 and 1904. The meteorological data collected during this period is still important for understanding Scottish mountain weather. C. T. R. Wilson was inspired to invent the cloud chamber after a period spent working at the observatory.