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 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 and to a scoring of the query string at the first global popularity chart; wherein the group of queries comprises queries which were queried during a first period of time.