The Big Build Adventure: Turning the UK’s Most Visited Digital Canvas into a Catalyst for Children’s Cancer Care
Outernet London
Client: Great Ormond Street Hospital (GOSH Charity)
Running across 6–31 August 2025, the activation used Outernet’s four-storey, 23,000 sq. ft digital screens to turn the NOW Building into a living construction site. Animated illustrations of the new Children’s Cancer Centre surrounded visitors, inviting them to play, paint, learn and contribute to the build. At the heart of the experience was a giant interactive Paint Workshop, where motion-tracking technology allowed visitors to virtually paint the hospital walls, symbolising collective action in building the future of children’s cancer care. A mobile web app unlocked via a QR code extended the experience with playful, build-themed games and social sharing, creating multiple entry points for engagement, data capture and donation, including the opportunity to “buy a brick” in support of the appeal. The campaign addressed an urgent need: cancer remains the biggest cause of death for children aged 1–14 in the UK, and Great Ormond Street Hospital’s (GOSH) pioneering breakthroughs have outgrown its current facilities. The Big Build Adventure reframed a complex capital appeal into an accessible, joyful and emotionally resonant public experience. The results demonstrated the power of immersive OOH to drive meaningful action. The campaign achieved over 210,000 impressions, significantly exceeded dwell-time benchmarks, and delivered exceptional brand recognition, advocacy and donation intent, proving that large-scale digital creativity can mobilise audiences at scale for good.