A millennial vision, often of some apocalypse or other negative event, is a common propaganda mechanism used near the turning of a millennium (in any calendar). As the year 1000 neared in Christian Europe, the sense that doom was near prompted much religious fervor and activity. Later in the 11th century, the feeling arose that Christ was overdue to claim his Kingdom, and such works as the Domesday Book began to be created, as an accounting of his realm.
The activity generally died out but is renewed (especially in the US and UK) at each turn of the century to a lesser degree, with some visions arising usually from various religious groups, and usually with fundraising appeals. This was very common in and around the year 1900, which some religious groups literally being founded strictly on the funds and fervor created.
In the year 1999, the fervor arose around the year 2000 and was bolstered by much propaganda around the so-called "Y2K" problem, or (more likely) fraud. Various predictions of doom were made and much cash was spent on rewriting code, doing good works, preparing for some disasters (that of course never occurred).
Many academic works of history and futurism sought to exploit the turning of the millennium, seeking to get prediction or summary of history in under the "deadline". Many non-governmental organizations, e.g. the United Nations University, sponsored Millennium Projects.
In 2001 some religious groups tried to revive this feeling as of the September 11, 2001 events, especially in the US. They were generally not successful.
A significant vision is that of global peace and cooperation. This has led to the habit in some quarters of referring to the present era as the Seventh Millennium.
A summary of millennial visions and projects around the year 2000 include: