Classrooms which address the needs of 21st Century learning are being developed for military, commercial, and public education applications. These classrooms are designed to support multiple modes of learning, to include: independent study, collaborative learning, mentoring, visualization, and immersive learning. In this paper, we describe how classrooms can support these multiple learning modes. The paper focuses on the design of the classroom infrastructure and its support for collaborative learning. This paper draws on two examples:

• WarLab XXI, an advanced classroom developed for the Battle Command Battle Laboratory under the direction of the Army Simulation Training and Instrumentation Command, and

• ALIVE, an advanced classroom developed by and for the Research Triangle Institute that focuses on the application of Virtual Reality (VR) and related technologies to enhance learning.

Both classrooms provide multiple learning environments, including an immersive classroom environment that supports group VR experiences, realistic work areas for simulations and "learning by doing," and support for remote access to allow distant learning. Both classrooms provide multiple networks that support sharing and presentation of multiple media between the instructor and the class. Both classrooms provide infrastructure to allow the instructor at a central location to control the media and to present student's work to other class members in a variety of forms. The WarLab XXI application supports a form of collaborative learning where specialists from different disciplines learn to cooperate in pursuing a common goal. In this context, specialists use a common virtual environment as a shared "3D blackboard" to integrate technical information for visualization by the students in the class.