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.
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There'll be bracing winds and heavy showers this afternoon and expect a wet and windy start on Monday morning.
Carl Edwards and guests look back at the week's events in the latest edition of Newsweek Wales.
A Yellow Warning has been issued by the Met Office as gale force winds and showery rain affect areas across Wales.