Final answer:
The 100th national anniversary of an event is called a centennial, which is marked by celebrations and recognition of the event's historical significance over a century
Step-by-step explanation:
The 100th national anniversary of an event is commonly referred to as a centennial. Celebrating a centennial involves recognizing and commemorating a century-long legacy since a significant historical event. For instance, the NAACP marked its centennial in 2009, celebrating 100 years of history, and the United States celebrated the bicentennial of its independence in the mid-1970s, honoring 200 years since the event.
These celebrations can take various forms, such as the creation of commemorative memorabilia, special events, and educational programs that reflect on the historical significance and impacts of the moment being remembered. The National Cherry Blossom Festival, for example, recognized its centennial by integrating the memories of individuals who had reached 100 years of age into a special performance that celebrated the history and cultural significance of the cherry blossoms in Washington D.C.