Britain's most famous landmarks were plunged into darkness on Monday night to mark 100 years since the start of WWI.
In the capital, the usually colourfully lit London Eye disappeared from view as the Lights Out event began at 10pm and ended at an hour later.
In the same hour, the nation was urged to switch off lights in places of worship, public buildings, workplaces and homes.
Only one light was left on- a candle lit outside No.10 Downing Street.
The nationwide event was designed to echo the words of then-foreign secretary Sir Edward Grey on the eve of the conflict: "The lamps are going out all over Europe; we shall not see them lit again in our lifetime."
And further north the lights were turned out on the spectacular Millennium Bridge in Gateshead.
Watch a video of the national Lights Out event below: