Every year, the International Maritime Organization celebrates World Maritime Day. The exact date is left to individual Governments but is usually celebrated during the last week in September. The day is used to focus attention on the importance of shipping safety, maritime security and the marine environment and to emphasize a particular aspect of IMO's work. To mark the occasion, the Secretary-General of IMO always prepares a special message and this is backed up by a paper which discusses the selected subject in greater depth.