Mr J Ll W Page, in his 'Exploration of Exmoor' (pub 1895), wrote :- "One of the most beautiful of Easter customs still survives. Young men have not yet ceased, on the Resurrection morning, to climb over the nearest hill top to see the sun flash over the dark ridge of Quantock, or the more distant line of Mendip.
"The sight of the newly risen luminary on this particular morning is to them an augury of good luck, as it was to the white robed Druid in the ages that are past. Early in the [19th] century, Dunkery, probably because it is the highest land in Somerset, was favoured above all surrounding hills, and its sides, says Miss King, were covered with young men, who seemed to come from every quarter of the compass and to be pressing up towards the Beacon."
From 'Calender of Customs, Superstitions, Weather Lore, Popular Sayings and Important Events Connected with the County of Somerset', by W G Willis Watson, 1920.
Five cairns of probable Bronze Age date are visible on the summit of Dunkery Beacon. The cairns were surveyed by English Heritage in August 2004 in response to a request by The National Trust and have been transcribed as closely as possible during the Exmoor National Mapping Programme survey. The group was previously recorded as both UID 35995 and 35990, but have now been combined into 35990 utilizing Grinsell's numbering scheme and with a concordance with the Scheduled Monument numbers.
I've not visited this site, but I understand that at 519 metres, Dunkery Beacon is the highest point on Exmoor (that's 1,706 feet if you're still using old money). The beacon is capped with two Bronze Age cairns.
This page contains a photo taken from Dunkery Beacon looking towards the coast. If you follow the Next Photo link there's a photo of the beacon itself with a cairn in shot. I'm not certain whether this is one of the Bronze Age cairns or a later addition.