Lights will go out across our region and the rest of the UK tonight between 10pm and 11pm - to mark the centenary of the outbreak of the First World War, writes Graham Walker.
In one of the most dramatic UK-wide events ever organised, it is hoped at least one million candles to be lit.
People are being encourage to turn off their lights and leave on a single light or candle for a shared moment of reflection and hope.
VIDEO: Press the play buton to watch the official Lights Out video.
The hour, between 10pm and 11pm, represents the final minutes of peace on August 4 1914.
Britain declared war at 11pm - midnight in Germany, when the ultimatum expired for them to get out of Belgium
Hundreds of venues, churches, war memorials and iconic buildings across the country are taking part. See local details below.
Families were also being encouraged to take part in their own homes.
For many it will be a time to remember ancestors, like those who joined the Pals battalions - those from the same towns who worked together, went off to fight together and, in many tragic cases, died together, wiping out a generation of men in some communities.
What will you be doing and who will you be remembering during Lights Out tonight? Leave a message below, or contact us by email and social network.
The inspiration for Lights Out came from a remark made on the eve of the outbreak of war by the then Foreign Secretary, Sir Edward Grey, who said: “The lamps are going out all over Europe; we shall not see them lit again in our life-time”.
Lights Out, supported by the British Legion, is a headline project of the cultural programme 14-18 NOW and was initiated by the Department for Culture, Media & Sport.
14-18 NOW is a curated programme of new art works across the UK that forms part of the official commemorations of the Centenary of the First World War. Visit www.1418now.org.uk/whats-on/lights-out/
Limited edition Centenary candles are available now from M&S stores for £4, with all profit coming to The Royal British Legion.
If you’re using your own candle and would like to make a donation, visit www.britishlegion.org.uk/get-involved/how-to-give, where you can also find details how to text a donation.
The Royal British Legion is hoping a million candles will be lit across the nation. Over 500 local authorities are taking part.
A spokesman for Lights Out said: “We hope to light one million candles across the UK to remember each and every one of those Service men and women who gave their lives in the war to end all wars. Please join together with us to create a unique national moment for the United Kingdom and The Royal British Legion.”
Westminster Abbey will be leading the nation with a First World War vigil liturgy which will be broadcast live on the BBC.
More than 50,000 men from Sheffield alone went off to fight, with the huge death toll from the war meaning only three parishes in the whole of Yorkshire saw all the men they sent to the front return safely.
In Sheffield a lone light will shine from the Town Hall and council offices at Moorfoot and Howden House between 10pm and 11pm.
In Doncaster, the Victoria Cross Trust is holding an event at its museum project at Askworth Barracks on Cedar Road.
At Billingley, near Barnsley, there will be a rememebrance evening event in the village hall which will include a display of memorabilia from the Great War. A booklet has been produced containing details of men from the village who served.
Thousands of individuals have joined together on Facebook to promise to observe the Lights Out event, which also has the support of Yorkshire MPs, writers, sports people, historians, servicemen and ex-servicemen and the families.
* Tell us why you are marking the occasion - and where - and let us know what happened to your family in the 1914-18 war.
Here are some of the events taking place locally tonight - for activits in your area visit www.1418now.org.uk/lights-out/search.
* Sheffield Town Hall, Pinstone Street, Sheffield, S1 2HH Council buildings in Sheffield city centre are set to take part in the national Lights Out initiative, to mark the hundredth anniversary of the beginning of the First World War. Between 10pm and 11pm on Monday 4 August, a lone light will shine from the Town Hall and council offices at Moorfoot and Howden House.
* Sheffield Railway Station/East Midlands Trains, Sheaf Street, Sheffield, S1 2BP, There will be a candle lit at Sheffield Railway Station in recognition of the railway workers that fought and died in the First World War. Sheffield Railway Station is just one of the stations participated in Lights Out on behalf of East Midlands Trains.
* Howden House, 1 Union Street, Sheffield, S1 2SH, Council buildings in Sheffield city centre are set to take part in the national Lights Out initiative, to mark the hundredth anniversary of the beginning of the First World War. Between 10pm and 11pm on Monday 4 August, a lone light will shine from the Town Hall and council offices at Moorfoot and Howden House.
* The Clock War Memorial, Stocksbridge, Sheffield S35 1QE, organised by Stocksbridge Royal British Legion and St Mathias’ Church, Stocksbridge. The British legion and members of the public are meeting at the War Memorial at 10.30pm for a service of remembrance and thanksgiving. Guests asked to bring a candle and the means of lighting it for a Vigil at the Memorial.
* Vulcan House, Riverside Entrance, 6 Millsands, Sheffield, S3 8NU. The Home Office will take part in LIGHTS OUT on 4 August: Various Home Office buildings will take part by switching off lights wherever possible and displaying a single light between 10-11pm.
* Moorfoot, The Moor, Sheffield, S1 4PL, Council buildings in Sheffield city centre are set to take part in the national Lights Out initiative, to mark the hundredth anniversary of the beginning of the First World War. Between 10pm and 11pm on Monday 4 August, a lone light will shine from the Town Hall and council offices at Moorfoot and Howden House.
* Mosborough Miners Welfare, Station Road, Mosborough, Sheffield, South Yorkshire, S20 5AD. Mosborough Rugby Club invites you to remember the fallen of Mosborough, Sheffield and sportsman everywhere. The ceremony will begin at 10pm 4th August 2014 and will take place on our rugby pitch. Please wear your favourite sports top as an act of remembrance to the sporting heroes who served during WWI.
* All Saints and St James Church, High Street, Silkstone, 12 High Street, Barnsley, South Yorkshire, S75 4JN, The church will be open from 10am until 5pm, and from 7pm until 11pm. Everyone is welcome to visit, light a candle, sit, pray and reflect. At 10pm we will hold the Lights Out vigil until 11pm.
* St John the Evangelist Church, Haigh Lane, Hoylandswaine, Barnsley, South Yorkshire, S36 7LW. The church will be open from 10am until 4pm. Everyone is welcome to visit, light a candle, sit, pray and reflect. At 10pm we will hold the Lights Out vigil until 11pm.
* Howden House, 1 Union Street, Sheffield, South Yorkshire, DE55 1DU. A light will be at a public entrance on First Point.
* Holy Trinity Church, Sough Hall Avenue, Thorpe Hesley, Rotherham, South Yorkshire S61 2QJ. Thorpe Hesley Lights Out moment will take palce at Holy Trinity Chruch, Thorpe Hesley, Rotherham starting with a servcie in Church at 10pm, followed by an Act of Remembrance at our war memorial. Candles will be provided however if you would like to bring one of the special candles please do so. This is an open invitation for those who live anywhere in Rotherham or near by to join us to mark this important time on our country’s history.
* 12th Barnsley Monk Bretton Air Scout Group, C/O 2 Nettlecroft, Monk Bretton, Barnsley, South Yorkshire, S715SD, Members of all four sections of the group will be taking a candle home to take part in the event with their families
* 7 Mill Street, South Kirby, Pontefract, West Yorkshire, WF9 3HN, Candle Lit service on Saturday 2nd August and Monday 4th August. Candles will be available
* Victoria Cross Trust, Ashworth Barracks, Cedar Road, Doncaster, South Yorkshire, DN4 9EY. The Victoria Cross Trust will be holding a Lights Out Event at its new museum project Ashworth Barracks on Cedar Road in Doncaster. Everyone is invited to attend and join in marking the start of the First World War in a very special way.
* C/O RBL HQ, Pine Close, Everton, Doncaster DN10 5DQ, A service at Retford War Memorial at 10.45pm on 4 August. The local churches are having a day of prayers for peace in a Retford Church and they are staying open so we can meet there for coffee etc before the event.
* The Parish Church of St Andrew, Station Road, Barrow Hill, Chesterfield, Derbyshire, S43 2NL, The church will be open on Sunday 3rd August from 2pm to 4pm for anyone to call in and light a candle. A candle-lit vigil based on the Westminster Abbey service will be held at 6pm and visitors will be given a candle as they leave and encouraged to take part in a community “Lights Out” moment the following day.
* Chesterfield Railway Station/East Midlands Trains, Corporation Street, Chesterfield, S41 7UB, There will be a candle lit at Chesterfield Railway Station in recognition of the railway workers that fought and died in the First World War. Chesterfield Railway Station is just one of the stations participated in Lights Out on behalf of East Midlands Trains.
* Worksop Market Place, Junction of Potter Street/ Park Street, Worksop, Nottinghamshire, S80 1HD, We will be assembling at 10pm for a candle lit commemoration. Selection of WW1 songs and poems commemorating the 100 year anniversary of Great Britain entering WW1 at 11pm on 4th August 1914. Followed by the candles going out remembering the words of Sir Edward Gray at the time ‘The Lamps are going out all over Europe; we shall not see them lit again in our life time’. It is to be a community event and is inclusive everyone is welcome to join us, please bring a candle or torch.
* C/O RBL HQ, Southgate Road Warsop, MANSFIELD, NG20 0QZ, Church service at 10pm on the 4th of August followed by a candlelit ceremony at the village memorial which will finish at 11pm. 300 people expected.
* Mansfield Museum, Leeming Street, Mansfield, Notts., NG18 1NG. Mansfield Museum will be marking LIGHTS OUT and commemorating the beginning of World War One with one single light in the front window.
Thousands of iconic buildings, landmarks and institutions across the UK have pledged their support to turn their lights off. These have included Blackpool Illuminations, Buckingham Palace, the Houses of Parliament, the Tate, Eden Project, the Imperial War Museums, Wales Millennium Centre, Tower Bridge, Durham Cathedral, Gateshead Millennium Bridge, Old Trafford, Lincoln Castle, The Royal Liver Building and the National History Museum. Across the City of London a number of buildings and offices went dark, including Bloomberg’s European headquarters and St Pauls’ Cathedral.