This paper presents a novel parameterized variety-based 3D exploration model to comprehend the sparse unstructured collection of photographs, and automatically plan virtual 3D tours of the world's landmarks through interesting viewpoints without explicit 3D reconstruction. The proposed system analyzes the collection of unstructured but related image data containing the same location or environment to create a parameterized scene graph: a data structure that conveys spatial relations and enable smooth virtual navigation between photos. A novel statistical-heuristic criteria is evolved exploiting the scene spatial layout and appearance to automatically identify best available portals between photographs. Once well connected, the graph is parameterized and consistently rendered choosing visually compelling 3D transition paths, maintaining a pleasing essence of parallax. The system's ability is demonstrated on several casually captured personal photo collections of heritage sites and imagery gathered from 'Flickr' data. © 2013 IEEE.