World maps span a length of time much longer than one would think. The first map to show the island of California is from a title page printed in 1622. One of the latest maps in the collection, from 1806, continues to depict the island in a school geography! World maps give one the chance to also view the projections being invented and in use during this time including the double hemisphere, Mercator, the heart-shaped Werner, polar projections, globe gores and more. The same map may appear more than once with subtle changes to the cartography, the date, the dedication, the page number, or the location of publication. These variations are known as states of the map where the copperplate engraving has been altered in some way to show different information.