Some go with the hope of bringing back gongs; others to do business deals or woo clients; many more just to see what all the bloody fuss is about.
One hopes they will also go, like me, in search of inspiration. But will we find what we seek?
Cannes Lions has evolved from a "Soho à la mer" shindig for British creatives into a genuinely international festival of creativity.
This is a good thing, not least for the festival organisers and the Mayor of Cannes, but also because this is the way the world is going.
Today, inspiration and game-changing commercial creativity can come from out of left field and from across international borders.
The danger is that the great ideas – the really great ideas – will be harder to find among the multilingual white noise
And there is the big question about whether we actually recognise brilliant thinking when we see it.
Sir John Hegarty, the founder of Bartle Bogle Hegarty and this year’s president of the Film Lions category, was recently musing with me about the difference between "promotional" ideas and truly "persuasive" ideas.
By persuasive, Hegarty is talking about transformational thinking; campaigns that transform a product or
an organisation from just so-so into a great brand; campaigns that become the driving force in our lives – literally so in the case of Bill Bernbach’s legendary 1959 "think small" campaign for the Volkswagen Beetle.
This is an appropriate definition of the "value" of advertising, in a world where value is increasingly hard to find.
Yes, data has some value to organisations, but only if they have some vision of how effectively to use that intelligence.
The current-affairs agenda shows the quite understandable, and growing, resistance that we have to organisations holding our personal data without explaining how this benefits us.
Yes, content has some value, but only if it is compelling, trusted content with some relevance to the brand from which it emanates. This is increasingly rare.
But insightful, challenging, brave thinking will always offer massive value. I would argue more so than ever in an age when economic growth is scarce. Let’s hope Cannes unearths at least a few examples of this.
You are reading Campaign’s first "global" issue, with major input from some of advertising’s best thinkers – and our own journalists – from around the world. It is designed to coincide with Cannes but is a taste of things to come.