Arquivo.pt created a calendar of historical/commemorative dates. Each date is marked by an event or celebration which is connected to an Arquivo.pt (or more) web page preserved about the theme.
Everyone can quickly access specific information about historic moments for Portugal and the world. In addition, everybody can collaborate by suggesting dates and relative pages, which will enrich the search.
Just import the calendar and receive daily notifications with the events and their Arquivo.pt preserved pages.
Give it a try!