The moment Britain declared war on Germany will be commemorated in a "national moment of reflection" on Monday night, with a mass public Lights Out event around the country.
Residents, businesses and other buildings are being asked to switch off their lights at 10pm to mark 100 years since the outbreak of World War One on August 4 1914 - leaving only a single light or candle on.
If you are taking part in the Lights Out commemoration, then we would like to share any pictures you may have with our readers.
Perhaps it will be an image of a candle in your home, or a street lit only by single lights in every window. Please email your photos to email@example.com, tweet @gethampshire or post on our Facebook page.
Hampshire County Council will dim more than 100,000 of its street lights between 10pm and 11pm. Major traffic routes will be exempt but some specific street lights will be switched off totally in the area of organised Lights Out events.
Councillor Seán Woodward said: "Hampshire played a key role in WWI as a major embarkation point for troops heading off to the battlefields in Belgium and France and it is fitting that we show our support for The Royal British Legion’s campaign.
"While not completely turning the lights out, the dimming will accentuate the effect of people illuminating a single lamp in their homes or local buildings across the county.”
Lights Out is part of the cultural programme 14-18 NOW, organised by the Department for Culture, Media & Sport, to mark the centenary.
The Royal British Legion hopes one million candles across the UK will be lit on the night to remember each soldier who lost their life in the Great War.
Late in the afternoon on August 3 1914, Foreign Secretary Sir Edward Grey stood at the window of his office in Whitehall and, as he watched the street lights being lit below, said: "The lamps are going out all over Europe, we shall not see them lit again in out lifetime."
Lights Out events:
- Step By Step, in Crimea Road, Aldershot, will be lighting a candle and reading passages from Forgotten Voices and World War One poems.
- Fleet, Crookham & District Royal British Legion and Hart District Council have organised candlelit vigils at the war memorials in Gurkha Square, Fleet, and Galley Hill Road, Church Crookham. Gally Hill Road will be closed from 9.30pm-11.30pm.
- A service will be held at 11pm at the Royal Garrison Church of All Saints in Aldershot.
- A candlelit service will be led by Sandhurst and District Corps of Drums at the memorial in Memorial Park, Sandhurst, at 9pm.
- Crowthorne Royal British Legion is holding a vigil at the war memorial at Lych Gate, St John the Baptist Church in Crowthorne, at 10pm.
- Guildford Cathedral is holding a special vigil, from 10pm, with guests of honour Their Royal Highnesses The Earl and Countess of Wessex.
- The floodlights will be turned off at Guildford Castle Great Tower.
- Woking Borough Council is holding a service of commemoration and reflection at Christ Church in Woking.
- Churches Together and Surrey Heath Borough Council will hold a requiem mass at St Tarcisius, Camberley, from 7.30pm.
- A candle vigil takes place at Bagshot War Memorial at St Anne's Church between 10.45pm and 11.15pm.
- Hawley and Frogmore Explorer Scouts will hold a candlelit vigil at Holy Trinity Church in Blackwater between 10pm and 11pm.
- A three-part candlelit vigil of Anticipation/Reality/Reflection will take place in Crookham Village between 10pm and 11pm at the parish war memorial, featuring readings of select news headlines, prayers and poems.
- There will be a wreath laying ceremony at Arborfield Cross War Memorial at 11am.
The unique gadget below allows you to search the full records of more than one million casualties of World War One.
The data comes from the Commonwealth War Graves Commission, who kindly allowed us to share the astonishingly rich data that they have painstakingly put together over the years.