In a 40-year collaboration, husband-and-wife artistic partners Anna Wilmsen and Wolfgang Kubach created multi-scale stone book sculptures to honor the history of the Earth. Using naturally occurring stones sourced from five continents, Kubach and Wilmsen ground, shaped, and polished fragments of stone into the likeness of books, which they classifed into two different canons. The first they called “Booktower”, consisting of groupings of various stone books in one unit, as in Booktower (2000/2001)—12 pieces sourced from around the world. The second canon, “Ikarus”, used single books to explore the concepts of circulation and continuous recycling, as in Ikarus Belgium (2006) which is made of Belgian-sourced marble. The duo saw their work as presenting a cross-section of the Earth's history, ultimately uniting each stone's place of origin.