On 4 August, between 10pm and 11pm, the whole country is being encouraged to turn off their lights, leaving on a single light for a shared moment of reflection.
Brent Civic Centre will be joining in by turning off all non-essential lights, as will Brent Housing Partnership.
Lights Out is being done to mark the exact point, 100 years ago to the very day, that Britain declared war on Germany, ushering in one of the darkest periods of our history.
As the moment approached, the British Foreign Secretary Sir Edward Grey made the famous remark "The lamps are going out all over Europe; we shall not see them lit again in our life-time".
Lights Out will be one of the largest participatory events of its kind ever seen in the UK and will complement the candlelit vigil held at Westminster Abbey on 4 August.
Special light and art installations have been commissioned all over the country. Millions of people are expected to participate in Lights Out and hundreds of local authorities, iconic buildings, national organisations including the BBC and the Royal British Legion have already pledged their support. Iconic buildings and landmarks such as Blackpool Illuminations, the Houses of Parliament, Eden Project, the Imperial War Museums and Tower Bridge will turn off their lights.
If you are planning on taking part in Lights Out, you can share your experience on twitter using the hashtag #LightsOut.