Fait mathématique: 2255 is the number of triangles of any size contained in the triangle of side 20 on a triangular grid.
Culture générale: 2255 is an uninteresting number.
Date historique: March 4th is the day in 1996 that a derailed train in Weyauwega, Wisconsin, US, causes the emergency evacuation of 2,300 people for 16 days.