1. A method for detecting a local phenomenon, the method comprises: creating, by a hardware chart generator, a first local popularity chart, wherein the creating of the first local popularity chart comprises enumerating, for each geographic area of a group of sampled geographic areas, identical query strings of queries that are included in a group of queries; creating, by the hardware chart generator, a first global popularity chart, wherein the creating of the first global popularity chart comprises enumerating identical query strings of the queries that are included in the group of queries and are associated with any one of the geographical areas of the group of sampled geographic areas; and selecting, by a hardware processor, at least one query string in response to a scoring of the query string at the first local popularity chart that indicates that the at least one query string is locally popular and to a scoring of the query string at the first global popularity chart that indicates that the at least one query string is not globally popular; wherein the group of queries comprises queries which were queried during a first period of time.