This paper uses a theoretical framework for concept mapping as an instance of a learning environment - the knowledge arena - and examines it against an existing framework for active learning called REAL (Rich Environment for Active Learning). The paper is intended to help in the understanding of environments for learning. Section 1 defines a knowledge arena as a virtual space where learners can operate on ideas, or concepts. This engagement involves a concept map. Section 2 describes concept maps and their use. Section 3 focuses on concept mapping and how it facilitates concept development and reflection. Section 4 examines concept mapping attributes. Section 5 defines learning environments and notes the attributes of REALs. Section 6 focuses on knowledge arenas and REALs, highlighting two consequences of what can be learned by using the knowledge arena as an example of a learning environment (the knowledge arena facilitates communication, and concept mapping influences the acquisition of cognitive skills in a knowledge arena). The paper concludes that concept mapping, construed as a knowledge arena, makes a useful contribution to understanding REALs and understanding learning. Similarly, REALs provide a useful framework for understanding concept mapping. (Contains 56 references.) (SM)