"Today’s ‘stone drop’ came about after Mr Black was contacted by London artist Henry Castle, who sent him an image of an engraved piece of Rubislaw granite sitting at the top of Ben Nevis - the highest point in the UK. Having taken the granite up Ben Nevis, Mr Castle wanted to take a piece of stone from the mountain, to what was once the lowest point of land in the UK, the bottom of Rubislaw Quarry - both stones therefore making the journey from the highest to lowest points in the UK and vice-versa.

Today, global subsea company Kongsberg will take the Nevis stone on a controlled descent to the bottom of the quarry with the help of a GPS positioning buoy. This will give it a unique GPS position, so it can always be located – and possibly viewed - with the aid of subsea technology."

Rubislaw Quarry.

The controlled descent took 2.29 minutes traveling at 1m per second. The quarry bottom hadn’t been seen since the quarry closed in 1971.