Advanced computing and imaging/sensing technologies enable scientists and researchers to study complex phenomena at unprecedented precision, resulting in an explosive growth of data. The size of the collected information about the Internet and mobile device users is expected to be even greater, a daunting challenge we must address in order to make sense and maximize utilization of all the available information. Visualization transforms large quantities of, often multiple-dimensional, data into graphical representations that exploit the high-bandwidth channel of the human visual system, leveraging the brain's remarkable ability to detect patterns and draw inferences. It has thus become an indispensable tool in many areas of study involving large, complex data. I will go over several exploratory and explanatory visualization designs introduced by my group for supporting a variety of data driven tasks found in real-world applications.