Ad agency McCann Melbourne with client Metro Trains won the top PR prize at the Cannes Lions awards in France today for their "Dumb Ways to Die" PSA campaign to curb accidents and deaths at Melbourne's Metro train station.

While PR shops won a handful of gold awards at Cannes, a PR firm has yet to win the top prize in the five years since PR was added to the competition.

The Metro campaign targeted young people 13-25 years old with an original song, "Dumb Ways to Die," attributed to a phony artist Tangerine Kitty and sold on iTunes. It was set to a YouTube video that garnered 20M views and was widely covered in Australian media. Its popularity soared beyond that country and made it onto Google's 2012 Zeitgeist.

Accidents and deaths fell 21% while campaign awareness among the target audience registered at 46%, according to a synopsis of the campaign, which is considered the most "shared" PSA campaign in history, logging 3M shares on Facebook and more than 2,000 blog posts.

Ketchum Europe CEO David Gallagher led the PR jury this year, which also awarded 20 gold, 29 silver and 28 bronze trophies.

Gold winners included Weber Shandwick for a crisis communications effort on behalf of the Design and Technology Association in the U.K., which aimed to avoid government cuts to the D&T curriculum in British schools.

Ketchum Pleon, Germany, won gold for a pro bono campaign with Friends of the Earth to benefit green group BUND that encircled an iconic Berlin chestnut tree with a device to amplify sounds and illuminate lights every time a chestnut fell off the tree.

Ogilvy Brasil, with help from Edelman, won gold with client Unilever for the Dove "Real Beauty Sketches" campaign, which launched on the "Today Show" in the U.S. and became a global viral hit showing women describe how they see themselves to an FBI sketch artist, contrasted with the description of the same woman by a stranger. A $240K budget generated 4.3M click-throughs to the Dove site and an estimated 3B media impressions.

Complete list of winners is at canneslions.com.