The archive · Advertising · Marketing decision · 2023–2024
JCDecaux turns a 100-year-old's 28-follower Instagram into metro ads — Cannes Grand Prix
To prove subway ads work, JCDecaux filled Madrid's unsold metro spaces with an unknown 100-year-old's Instagram — she became famous, brands returned.
JCDecaux Spain · DAVID Madrid
What it had to solve
JCDecaux Spain wanted to reverse a drop in Madrid subway advertising investment and convince C-suite marketers that out-of-home media is worth buying — but B2B advertising normally argues this with data, not with people.
How it works
Madrid woke up in late 2023 to a mystery: photos of an unknown 100-year-old woman watering plants, eating churros and taking naps had appeared overnight across the metro's empty advertising spaces. Nobody knew who she was or why she was there, and thousands of commuters searched for her, followed her and posed for selfies with the posters.
The woman was Marina Prieto, a Galician grandmother whose real Instagram account had just 28 followers, mostly family. DAVID Madrid had found her while looking for 'the most generic person possible' and, together with JCDecaux Spain, put her 54 posts into the advertising slots brands hadn't bought. There was no logo, product or call to action — only the question of who she was. The stunt was the pitch: JCDecaux's B2B brief was to prove that out-of-home media still works, so the agency made the campaign itself the proof.
The results convinced the industry. Marina's following grew +39,285% with +13,405% engagement; 92,000 unique accounts interacted with her in a month. JCDecaux says media investment in its OOH space doubled, more than 180 brands including Havaianas, Samsung and HBO Max returned to the Madrid metro, and bookings reached records. The campaign won the Creative B2B Grand Prix and the Dan Wieden Titanium Lion at Cannes 2024 — the first Spanish campaign to take the B2B Grand Prix — plus four Grand Clios and a D&AD Graphite Pencil.
Why it lands
- An unknown woman with 28 followers is the hardest possible proof case: if the medium can make her famous, it can make any brand famous.
- No logo, product or CTA leaves a question mark that commuters answer by searching and sharing — earned attention instead of paid interruption.
- Using unsold inventory turns dead media space into the campaign's own stage, so the budget and the message are the same thing.
- A sweet, human story aimed at C-suite marketers works because B2B decisions are still made by people.
What it did
Marina's following grew +39,285% with +13,405% engagement; her Instagram went from a few followers to over 10,000, with 92,000 unique accounts interacting within a month and more than 400,000 impressions in one week. JCDecaux says media investment in OOH doubled, 180+ brands including Havaianas, Samsung and HBO Max returned to the metro, and bookings hit records. The work won the Creative B2B Grand Prix and Dan Wieden Titanium Lion at Cannes 2024 and four Grand Clios in 2025.
What you can take
When you sell a medium, don't argue with data — run the campaign as the evidence: make a nobody famous with your own unsold inventory, and let the result sell the product.
Since then
Marina Prieto became a public figure — fans sent birthday wishes, students made final projects about her, and one fan asked her to record a wedding video. The campaign kept winning through 2025: four Grand Clios, the ANDY Awards Grandy, and a Cannes Bronze in Creative Strategy, while JCDecaux used it as the flagship case for reviving Spanish OOH investment.
Sources
- Further winners announced on day three of the Cannes Lions International Festival of Creativity
- How a 100 Year-Old Spanish Grandmother Amped OOH for JCDecaux
- JCDecaux Spain receives 6 awards at Cannes Lions, including the Dan Wieden Titanium Prix for its 'Meet Marina Prieto' campaign
- JCDecaux: Meet Marina Prieto
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