Visualization and machine learning are both essential tools for data mining. We argue that there is actually a close connection between the two. We start by giving a quick review of the state of the art for large graph visualization. We then look at how to use visualization technique, including graph and map visualization, to help explain machine learning techniques such as recommender systems and gender/ethnicity classifiers. Finally we look at how to use a successful technique from visualization to improve deepwalk, a machine learning algorithm.