Watch Caron Bell's report.
Major conservation work is starting at Stonehenge for the first time in more than 60 years.
A team of specialist stonemasons has been brought in to repoint old mortar and fill in cracks and holes.
Heather Sebire, senior curator at English Heritage, is keen to point out that the stones are still perfectly safe and in no danger of falling over.
She said: "It's really just conservation rather than restoration.
"Nothing's going to change about Stonehenge but we're just making sure the lintels stay bedded on top of the huge uprights, and that we prevent water puddling on the top of them."
The stones at the landmark have been battered by the elements for 4,500 years and are holding up – but the repairs done to stabilise them in the 1958 are not.
Stonemasons, including James Preston, will replace the 1950s cement with a stronger formula and try to stop surface erosion on the stones from getting any worse.
He explained: "So you can see here the mortar from works in the fifties and sixties, and where some of it has either eroded or deteriorated over time, we're going to deal with the defects arising and repair the mortars that need repairing.
"I've been in this business, in this company, for 20 years and this is a huge highlight for us."
Entire lintels were hoisted off and stuck back on during the 1958 project, during which a boy called Richard was invited to place a halfpenny beneath a repaired sarsen (sandstone block).
More than half a century later and Richard is back - this time with a £2 coin specially minted for him to bury under a lintel.
He said: "What a privilege it is for English Heritage to invite me to do this and indeed the Royal Mint, to strike the actual coin.
"It's always a delight to see such a fantastic monument because it's so interesting."