Wunderman Belgium and Child Focus, a Belgium organization focused on preventing and supporting missing and sexually exploited children, teamed up to print the face of a boy who has been missing in the country for two decades on one million 2 Euro coins.

The "Coins of Hope" initiative, which took two years to complete due to approval processes of the Ministry of Finance and all European countries, launches on May 25 in recognition of the International Day of Missing Children. The day evolved from the Day of Missing Children in the U.S. in 1998, created four years after the disappearance of original milk carton boy Etan Patz, to an international day in 1998.

The face on the coin depicts what Liam Vandenbranden, who went missing at two years old, might look like today. "This is absolutely about Liam, but he has become a face for a much larger challenge," said Wunderman Global CCO Lincoln Bjorkman. "The problem is international in scale and currency is a wonderful channel because by its very nature it is large, scaled and it moves."

Belgium Minister of Finance Johan Van Overtveldt said via email that commemorative coins are issued across Europe every year, but rarely with a message as "as symbolic and outspoken as this one."

"This isn't just a commemorative coin, these are 'hopeful coins,'" he said. "This coin is the symbol of all our missing children and by using and spreading these coins we spread awareness and hope to find these children and bring them back home."

To build buzz about the coins, which are meant to be spread and not become collector's items, the King and Queen of Belgium are expected to speak about the effort. The coins will be distributed directly from the checkout system of LIDL supermarkets in Belgium, where signs about the campaign will be hung. Wunderman created a short video showing the coin that will run online and on the tail-end of several TV spots in the country, as well as two other videos for online use only with stories from parents.

On social media, people are encouraged to take a selfie with the coin if they have it and post #CoinsofHope to help spread the message beyond Europe. For those who don't have access to the actual coin, they can go on www.coinsofhope.be and turn any coin in a selfie photo into the one with Liam's face.

Mr. Bjorkman said the agency was moved that so many government officials were willing to get behind the campaign and actually change currency.

"This is pay it forward, literally. The goal of the campaign is simple -- nothing moves like small currency. Put the idea on currency and we believe the idea will move," said Mr. Bjorkman.

"Sometimes our business can be extremely cynical, so it's reassuring to see how many people immediately asked how to help. It's empowering and moving," said Mr. Bjorkman.

Other agencies have devoted their creative ingenuity to the search for missing kids. BBDO partnered with the NYPD and recently placed the face of a missing child on a mannequin in a New York city storefront. A couple years back, VML cleverly transformed the typical pre-roll "skip ad" button into a means for people to report that they've seen a missing child.