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
All primary and secondary schools in Wales have been categorised in a new colour-coded system. Is your school green or red?
A yellow warning for snow and ice on Thursday night and Friday has been issued.
Some wintry showers and staying windy with a significant wind chill and widespread frost developing