We introduce an on-line framework for the visualizing of underground structures that improves X-Ray vision and Focus and Context Rendering for Augmented Reality. Our approach does not require an accurate reconstruction of the 3D environment and runs on-line on modern hardwares. For these purposes, we extract characteristic features from video frames and create visual cues to reveal occlusion relationships. To enhance the perception of occluding order, the extracted features are either directly rendered, or used to create hybrid blending masks: we thus ensure that the resulting cues are clearly noticeable. CR Categories: I.3.7 [Three-Dimensional Graphics and Realism]: Virtual reality--Augmented Reality;