A Snowdonia peak has leapt into the ranks of "super-mountain" after amateur surveyors found it is a crucial 1.8m (about 5ft 11in) higher than thought.
It takes Glyder Fawr in the Snowdonia National Park up from 999m (3,278ft) above sea level to 1000.8m (3,283ft).
That makes National Trust-owned Glyder Fawr Wales' fifth "super mountain".
A spokesman for the Snowdonia National Park said it was now sure to attract more walkers and adds another mountain to the Welsh 1,000m peaks race.
Enthusiasts scaled it with GPS equipment in an attempt to "find" the extra height to make the grade.
A spokesman for the park explained that Ordnance Survey usually measures the height of a mountain using a "photogrammetry" method where detailed aerial images are taken to create 3-D images of the countryside.
He said that the method was not thought to be detailed enough, however, and can be 3m higher or lower than the correct height.
The Glyder Fawr measurements were taken by national park staff who trapped a global positioning system (GPS) antennae to the side of the summit rock.
Signals received from satellites orbiting 22,000km (13,670miles) above the earth are then used to calculate a more accurate measurement.
"We are extremely pleased that G & J Surveys have gone to so much trouble to ensuring a correct measurement for Glyder Fawr," said Emyr Williams, director of land management with the Snowdonia National Park Authority.
He said the new measurement would mean "new obligations" for the park authority from a land conservation and management perspective.
"We now have a fifth peak in Snowdonia which is higher than 1000m and as a result it is sure to attract more walkers to this area, and it also adds another peak to the Welsh 1000m peaks race," he said.
The "challenge" would be to ensure the area's special qualities will be carefully protected," he added.
Rhys Evans, the Snowdonia manager for the National Trust, said the new height was a "significant announcement" that would raise the mountain's status.
"It will also provide a welcome boost to the number of visitors to the area, which will hopefully have a positive impact on the the local economy," he added.
G and J Surveys also measured nearby Tryfan earlier this year, and found it is 917.5m (3,010ft), or 2.5m (8ft) higher than previously thought.