An Ulster Museum curator has discovered the first meteorite impact crater in the UK, and it is one of the largest in the world.
Dr Mike Simms, a palaeontology specialist, started on the path to the discovery during a geological holiday in Scotland in 2011.
He and a friend were going to visit a rock formation more than a billion years old. It was initially believed to have been formed by volcanic mudflow, but in 2008 geologists from Oxford and Aberdeen found it was the result of a meteorite impact.
When Dr Simms was on his holiday, he spotted a number of things that had not been noticed before, leading him to believe the crater was to the east and not to the west, as experts previously believed.
After some "geological detective work", including studying the rock formation and geophysical maps, Dr Simms found that the crater was most likely beneath the village of Lairg.
A gravity anomaly found under the village also matched the type of disturbance that would have been caused by a crater.
The impact is the first to be discovered in the UK and is more than 40km across, making it one of the 15 largest impact craters on Earth.
Dr Simms said that he never expected to discover anything so enormous when he went on holiday.
"It shows the importance of chance - you can't predict what kind of discoveries you're going to make," he explained.
The expert, who has been collecting fossils since he was six, was simply doing what he loved. "I tend to just follow things I find interesting," he added.
The story will be shown on Walking Through Time on Channel 4 at 8pm on Saturday.