The Happy Cloud installation filled the air outside the Tate Modern Gallery in London with smiley faces made from helium, soap and vegetable dye.
The artist, Stuart Semple, interviewed by Telegraph TV in the video below, said he wanted to create something to cheer people up.
As well as alleviating the doom and gloom of recessions and downturns, the installation aims to show that creative industries have an important role in the economy and should not be neglected during the recession.
Some things in life are bad.
They can really make you mad.
Other things just make you swear and curse.
When you're chewing on life's gristle.
Don't grumble, give a whistle.
And this'll help things turn out for the best...
Always look on the bright side of life...