Changes have been made in education systems within the changing and developing structure of our age. In this context, while achieving 21st century skills is among the most important achievements, determining the activities to be prepared for students to acquire 21st century skills and arranging the classroom environments according to these activities impose new and important tasks on teachers. In this study, evaluations based on a performed activity are presented in the context of the integration of 21st Century Skills into Turkish National Education system. The "Where are we?" activity which is presented in detail in the study is an interdisciplinary activity carried out in Mamak Science and Arts Centre with 4th graders. The activity is described in three steps, namely preparation, implementation and evaluation, and its significance in providing students with 4C (Creativity, Communication, Critical Thinking and Collaboration) skills, which are regarded as the foundation of 21st Century Skills, is underlined. The activity is also evaluated in terms of applicability and popularization, and special emphasis is put on the importance of class environment in gaining 21st Century Skills. Within this framework, it is recommended to enhance teacher trainings and activity samples in quantity and quality for the acquisition of 21st Century Skills in students and also suggestions were made to policy makers for the process of integrating 21st century skills into the education system. The study has a unique structure as it is exemplified through an activity example. It is thought to be a resource for all academicians, teachers and policy makers interested in the subject.