1. A method of building a geo-tree structure, wherein a geo-tree corresponds to a logical tree having nodes comprising geographic information, comprising: using a plurality of first media items each having at least media, a geographic tag, and a contextual tag to assign geographic information to a second media item having at least media and a contextual tag but without a geographic tag by collecting the plurality of first media items; associating the geographic tags of the plurality of first media items with the contextual tags of the plurality of first media items, wherein the contextual tags of the plurality of first media items and the second media item include words or terms describing content of the media of the respective one of the plurality of first media items and the second media items, and wherein at least one same word or term of the contextual tags of the plurality of first media items are associated with a plurality of geographic tags; clustering the collected first media items based on the association of the geographic tags of the plurality of first media items with the contextual tags of the plurality of first media items; classifying the clusters using at least one of the words or terms of the contextual tags of the plurality of first media items; building a geo-tree with each classified cluster being associated with a node on the tree, wherein the nodes of the geo-tree comprise geographic information; storing the geo-tree on a computer readable medium; and assigning the second media item to a cluster in the geo-tree based on words or terms in the contextual tag associated with the second media item matching a word or term of one of the classified clusters so that the second media item is associated with the geographic information of the node of the assigned cluster.