Knowing the living environments is an intrinsic part of human development for building self-confidence and meeting social requirements. Proliferation of mobile devices has greatly changed our interaction with the physical environments. Existing mobile tools largely emphasize navigation support with step-by-step route directions, and are often weak in terms of helping people better understand the place. Such approach is inadequate in situations like moving to a new city where people need to build comprehensive awareness of the environment. In this paper, we propose a place-sensemaking design framework to facilitate the process of maintaining awareness of the environment and building comprehensive knowledge of the place. In this study, we have taken a multi-disciplinary research approach to develop a design framework, to build a mobile application, and to evaluate the use of new technologies. First, we extended sensemaking theories from information science to the domain of physical navigation. This framework suggests that to create comprehensive understanding of the place, computational tools need to provide not only spatial information, but also the social and temporal information of the place. Second, guided by the framework, we designed and implemented a mobile application on the Android platform to facilitate place sensemaking by integrating multiple online resources, such as Facebook, Foursquare, Panoramio, and Wikipedia.