Collaborative knowledge building is an approach to teacher professional development that taps into teachers' expertise and invites them to make advances into teacher knowledge using electronic tools. A series of Websites offering multimedia virtual visits to look in on selected aspects of Knowledge Forum® databases highlight knowledge building moments in databases and classrooms where teams of students are working collaboratively to achieve a deep understanding of curriculum content. Teachers and students’ annotations will provide visitors with an understanding of how learning takes place in social school settings where talk and action among learners with different skills motivate intellectual development. As well, teachers’ reports of their classroom experiments will allow both the teachers creating virtual visitations and the teacher audience to reflect on what teaching strategies worked best. These websites will provide opportunities to be referred to in either a face-to-face or on-line mode in formal and informal professional development programs and activities.