In a rural health center in Kenya, a community health worker develops an innovative approach to reaching families who have been hesitant about vaccination. Meanwhile, in a Brazilian city, a nurse has gotten everyone involved – including families and communities – onboard to integrate information about HPV vaccination into cervical cancer screening. These valuable insights might once have remained isolated, their potential impact limited to their immediate contexts. But through Teach to Reach – a peer learning platform, network, and community hosted by The Geneva Learning Foundation – these experiences become part of a larger tapestry of knowledge that transforms how health workers learn and adapt their practices worldwide. Since January 2021, the event series has grown to connect over 21,000 health professionals from more than 70 countries, reaching its tenth edition with 21,398 participants in June 2024. Scale matters, but this level of engagement begs the question: how and why does it …