The Human Genome Project brought researchers together worldwide
President Bill Clinton, Francis Collins (NHGRI) and Craig Venter at the 26 June 2000 announcement of the working draft. NHGRI photo, public-domain status indicated on Wikimedia Commons; creator and date credited. No edits. https://commons.wikimedia.org/wiki/File:IHGSC_Human_Genome_Project_Draft_Completion_Announcement_-_June_2000.jpg
The Human Genome Project officially began on 1 October 1990 as a joint program of the U.S. National Institutes of Health and Department of Energy. Scientists from other countries later joined the international work, including the Wellcome Trust Sanger Centre in Britain; the project was completed in 2003. Wellcome describes it as the largest international collaboration in biology, but this is a characterization of the project’s scale, not a formal ranking of all scientific collaborations.

