Scientists say they believe they have captured the elusive Higgs Boson particle that gives matter mass.
Professor John Womersley, chief executive of the Science and Technology Facilities Council, told reporters at a London briefing that they had discovered a particle consistent with the Higgs Boson.
Discovery is the important word. That is confirmed. It's a momentous day for science.
There is a strong Welsh connection to the groundbreaking scientific project as Dr Lyn Evans from Aberdare was the project leader.
More top news
Cardiff's Millennium Stadium issues "do's and don'ts" ahead of One Direction's gigs in the city in two week's time. Don't be caught out...
Welsh Assembly Members who are elected in 2016 will get a £64,000 basic wage. But the 18% rise is too much for some of them.
A largely cloudy afternoon with some drizzle in the north. Clearer spells developing during the evening and overnight.