The 420 Collaboration is an annual campaign to "create and improve cannabis-related content at Wikipedia and other Wikimedia projects in a variety of fields", including culture, health, hemp, history, medicine, politics and religion. Campaigns were held in 2017, 2018, and 2019. The 2020 campaign runs during April, and is being organized around curated lists of redlinks or at-will article creation and improvement on English Wikipedia (or media contributions to Wikimedia Commons).