A method for reducing an amount of storage required for maintaining a large-scale collection of multimedia data elements by unsupervised clustering of multimedia data elements. The method comprises processing the multimedia data elements in the large-scale collection to generate a first cluster of multimedia data elements; storing the first cluster in a storage unit; repeating the generation of a new cluster from the first cluster and un-clustered multimedia elements in the large-scale collection until a single cluster is reached; and storing the new cluster generated at each iteration in the storage unit, wherein a N-th cluster generated at the N-th iteration is stored in the storage unit, wherein the amount of storage required to store the N-th cluster is less than an amount of storage of the large-scale collection, thereby the unsupervised clustering enables reducing the storage amount required to store the multimedia data elements in the large-scale collection.