Visualizing and analyzing geospatial and temporal observations are common tasks for many application domains. In this paper, we introduce UFO Tracker, a visual analytic tool for analyzing unidentified flying object sightings from the National UFO Reporting Center. The goal here is to give the user a higher level view of where different types of sightings occur, to investigate whether sightings are increasing or decreasing over time, to discover the connections between different events which might happen at different geographic areas