For details of current and forthcoming exhibitions in the real world see John Docktor's listing. If you want historical information, follow links from the head of that page to the separate listings for exhibitions that closed in previous years. The Brussels International Map Collectors' Circle [BIMCC] maintains a register of International news and events (including a section on Exhibitions).

Also see the Smithsonian Institution's excellent 'Library and Archival Exhibitions on the Web'. "This site features links to online exhibitions that have been created by libraries, archives, and historical societies, as well as to museum online exhibitions with a significant focus on library and archival materials". You can search the featured exhibits (from 1995 onwards and mostly in the US) individually or, in 'Subject', by, e.g. 'maps' or 'exploration'. In September 2007, there were over 5000 entries. Check regularly for 'Recent Additions'.