The real-world big data are largely unstructured, interconnected, and dynamic, in the form of natural language text. It is highly desirable to transform such massive unstructured data into structured knowledge. Many researchers rely on labor-intensive labeling and curation to extract knowledge from such data, which may not be scalable, especially considering that a lot of text corpora are highly dynamic and domain specific. We believe that massive text data itself may disclose a large body of hidden patterns, structures, and knowledge. With domain-independent and domain-dependent knowledge bases, we propose to explore the power of massive data itself for turning unstructured data into structured knowledge. By organizing massive text documents into multidimensional text cubes, we show structured knowledge can be extracted and used effectively. In this talk, we introduce a set of methods developed recently in our group for such an exploration, including mining quality phrases, entity recognition and typing, multi-faceted taxonomy construction, and construction and exploration of multi-dimensional text cubes. We show that data-driven approach could be a promising direction at transforming massive text data into structured knowledge.