A method, implemented by a system coupled with a wireless telecommunication network, of estimating a number of persons that gathered at an Area of Interest for attending a public happening during a time interval on a day, wherein said Area of Interest is defined by an Area of Interest center and an Area of Interest radius and is covered by a mobile telecommunication network having a plurality of communication stations each of which is adapted to manage communications of user equipment in one or more served areas in which the mobile telecommunication network is subdivided, the method comprising the steps of: a) defining ( 504, 506, 530 - 534) a plurality of calculated radius values of the Area of Interest radius, and, for each calculated radius value: b) identifying ( 510, 512) a first number of user equipment associated with at least one event record of a corresponding event of interaction occurred between the user equipment and the mobile communication network during the time interval on the day within the Area of Interest; c) identifying ( 514, 516) a second number of user equipment associated with at least one event record of a corresponding event of interaction occurred between the user equipment and the mobile communication network during the time interval for each day of a predetermined number of previous days preceding the day within the Area of Interest; d) combining ( 518, 520) the first number of user equipment and the second numbers of user equipment for obtaining a statistical quantity; e) detecting ( 522, 524) an occurrence of the public happening if the statistical quantity reaches a certain threshold; f) computing an optimum radius value of the Area of Interest radius as the average of the calculated radius values within which the public happening is detected; g) counting the number of persons, owners of user equipment, that gathered for attending at the public happening within the Area of Interest having the Area of Interest radius equal to the optimum radius values. a) defining ( 504, 506, 530 - 534) a plurality of calculated radius values of the Area of Interest radius, and, b) identifying ( 510, 512) a first number of user equipment associated with at least one event record of a corresponding event of interaction occurred between the user equipment and the mobile communication network during the time interval on the day within the Area of Interest; c) identifying ( 514, 516) a second number of user equipment associated with at least one event record of a corresponding event of interaction occurred between the user equipment and the mobile communication network during the time interval for each day of a predetermined number of previous days preceding the day within the Area of Interest; d) combining ( 518, 520) the first number of user equipment and the second numbers of user equipment for obtaining a statistical quantity; e) detecting ( 522, 524) an occurrence of the public happening if the statistical quantity reaches a certain threshold; f) computing an optimum radius value of the Area of Interest radius as the average of the calculated radius values within which the public happening is detected; g) counting the number of persons, owners of user equipment, that gathered for attending at the public happening within the Area of Interest having the Area of Interest radius equal to the optimum radius values.