The detections of gravitational waves, which culminated in the 2017 physics Noble Prize award have again con-firmed the triumph of the general relativity theory. This theory, together with quantum mechanics, forms the backbones of our modern understanding of the world and significantly contributes to modern technologies we are using today. Despite the importance of these theories, they are still rarely part of high school physics curricula worldwide, including the Indonesian physics curriculum. This is due to the assumption that these theories are too difficult for students to grasp. However, there has been a growing interest to bring these theories to younger students and the general public. There is growing evidence that appropriate teaching can result in measurable learning. The purpose of this research was to explore the impact of activity-based learning using models and analogies on high school students’ conceptual understanding of general relativity related concepts. The research was an exploratory study conducted in one class of 31 students who participated in three weeks program. Testing of their conceptual understanding used identical pre/posttests. The results indicated a strong and statistically significant improvement in students’ conceptual understanding with a large effect size. Interestingly, the results showed that the change in the physics conceptual understanding of girls was higher than boys. The results of this program indicate that further research can be conducted with a larger number of students and in a longer period and thus provides a promising prospect for future research in Indonesia.