Speech databases lack efficient interfaces to explore information along time. We introduce an interactive timeline that helps the user in browsing an audio stream on a large time scale and recontextualize targeted information. Time can be explored at different granularities using synchronized scales. We try to take advantage of automatic transcription to generate a conceptual structure of the database. The timeline is annotated with two elements to reflect the information distribution relevant to a user need. Information density is computed using an information retrieval model and displayed as a continuous shade on the timeline whereas anchorage points are expected to provide a stronger structure and to guide the user through his exploration. These points are generated using an extractive summarization algorithm. We present a prototype implementing the interactive timeline to browse broadcast news recordings.