Staff are the heart of your anniversary. The more involved they are, the more they experience the event as 'theirs'. And that hugely strengthens pride and connection.
Practical ways to involve staff: put together an anniversary committee with colleagues from different departments. Collect personal stories and anecdotes for a retrospective. Give staff an active role during the programme. Organise an internal campaign in the run-up to the anniversary.
During the anniversary itself, interactive elements work well. Think of a photo wall with memories, a live poll, a shared ritual or a surprise from the team for the board.
The finest anniversary is one where everyone feels part of it. Not just as a guest, but as a co-creator.