Europe's highest art installation will be switched on at 5pm this afternoon in London.
The display called 'Shard Lights' will illuminate the western side of the top 40 floors and the spire of the Shard, Western Europe's tallest building.
Designers say the display will make the Shard "come alive with a dynamic piece of public art designed to reflect and evoke the spirit, energy and dynamism of London".
It comprises eight high power search lights, 184 giant LED 'pixels', 68 colour changing moving lights, 184 strobe lights and ten of the world's largest smoke machines.
It has taken sixty people, seventy-two hours to install the light display, which uses seven kilometers of cable.
The 300,000 watt display was designed by Jason Bruges Studio:
Shard Lights will create a theatre in the sky, and it will be a prominent feature of the London skyline for the twelve days of the project.
Irvine Sellar, developer and shareholder of The Shard, added:
The Shard has become a beacon for modern London, and is globally recognised as an emblem of our capital.
The lights countdown to a firework display to mark the New Year celebrations and welcome in 2015 the UN's 'International Year of Light'.