The Catalogue of Life, started in June 2001 by Species 2000 and Integrated Taxonomic Information System (ITIS), is planned to become a comprehensive catalogue of all known species of organisms on Earth. The Catalogue currently compiles data from 158 peer-reviewed taxonomic databases, that are maintained by specialist institutions around the world. The Catalogue provides a dynamic edition, which is updated regularly (and in which data can change without tracking of those changes) and an Annual Checklist, which provides a dated, verifiable reference for the usage of names and associated data. Development of the Catalogue of Life was funded through the Species 2000 europa (EuroCat), 4d4Life and i4Life projects in 2003-2013.