Monday, August 4, is the 100th anniversary of the start of the First World War when the UK declared war on Germany.

The country emerged utterly changed four years later – grieving for one million Commonwealth dead, even more injured.

There can be few local families who did not have relatives who served, fought, died and suffered in the 1914-18 conflict that introduced the bombing of civilians, machine guns, poison gas and tanks to warfare.

Across Hampshire, cities, towns and villages will this weekend and on Monday pause to reflect on the war.

Throughout the region, churches are holding special services and candlelit vigils, while veterans’ associations will lay wreaths at memorials and councils are organising exhibitions. People are also being invited to take part in the nationwide ‘Lights Out’, switching off for an hour from 10pm to 11pm on Monday, the moment the UK declared war, to encourage reflection.

They are being asked to leave just one candle burning in a window. It references the prophetic remark by Sir Edward Grey, Foreign Secretary, on the eve of war: “The lamps are going out all over Europe; we shall not see them lit again in our lifetime.”

Sir Edward had a fishing hut at Itchen Abbas, near Winchester, where he spent the night of August 3, 1914, before travelling to London to announce the entry into war.

In Southampton the floodlights at the Cenotaph on Above Bar will be switched off between 10pm-11pm. A vigil will be held there.

Archie Parsons, former secretary of the Southampton branch of the Royal British Legion, said: “I’m not aware of anything else the city council is planning, unfortunately. It is a great shame and very sad.”

In Eastleigh the town branch of the Royal British Legion will gather at the war memorial in Eastleigh Park at 10pm for a vigil.

They have asked the funfair visiting the park to turn off the music at 10pm. Brian Godwin, branch chairman, said: “Hopefully there will be quite a few there. The legion was created in 1921 because of what happened in the First World War.

“We feel we need to mark August 4 as a mark of respect to those who fell and those who have died in conflicts since.”

In Winchester the cathedral will hold a lantern-lit vigil from 10pm-11pm.

Winchester Planetarium at Morn Hill has Civil Aviation Authority clearance to project a high-intensity light beam on to the Science Centre.

The city council has also commissioned a light installation, ‘Box 459’, designed by local firm AR Design Studio, with 459 holes, the number of dead from the city. It will be unveiled at 9.30pm on Monday.

Jewry Street Art Café is inviting people to attend a candlelit sculptural exhibition of work by Robert Truscott.

Winchester Quakers are staging an outdoor exhibition at the Friends’ Meeting House on Colebrook Street, telling the story of Britain’s conscientious objectors.

On Monday the chairman of Hampshire County Council, Colin Davidovitz, will host a ‘Hampshire Commemorates’ exhibition in the Great Hall, showcasing historic materials.

It will from 10am to 5pm provide a taster of some of the exhibitions around the county.

On Sunday, August 3, the villages of Compton and Shawford will stage a Great War Day on the Memorial Playing Fields, Compton.

In Romsey, Test Valley Borough Council will turn off the lights at key buildings and leave just one single light on at Crosfield Hall, the former Magistrates’ Court and Romsey Rapids.

Cllr Ian Carr, council leader, said: “The council is honoured to be a part of this event, which encourages reflection and respect for those who fought.”

In Awbridge a short ceremony will be held at the war memorial on Romsey Road at 7pm.

King’s Somborne is staging an exhibition through August at the parish church, organised by the Somborne and District Society.

Mary Pollock and Norman Denison have been researching the Great War and how it affected the Somborne Valley and an 80-page commemorative booklet has been produced.

In Fareham, the borough council has organised a number of events.

Doves will be released and The Last Post played as mayor David Norris unveils a new commemoration stone in West Street.

Wartime tea and cakes will be served in Holy Trinity Church alongside a display of photos by local photographer Innes Marlow entitled The Lost Sons of Fareham.

It shows the headstones of soldiers whose names are on the war memorial and whose graves are in French or Belgian cemeteries.

At Sarisbury Green United Reformed Church the centrepiece will be a ‘Garden of over 200 Knitted Poppies’ created by church members.

St Mary’s Church, Warsash, will be holding an all-day vigil on Monday from 9am to 7pm