The 21st-century learning emphasises students to be active, engaging, collaborative and has critical thinking skills. Learning the Cryptography concept able to promote students to think critically. However, learning History at schools is considered dull and boring, and requires students to memorise many historical facts and events. Therefore, this study proposed a heliographic treasure hunt board and clues as a learning aid tool and expected it could be used to learn Cryptography as well as History. An expert review was conducted to gain insight on the heliographic treasure hunt board and clues and the possible ways to improve it. Six experts from both history and cryptography backgrounds participated in this review process. Findings show that the experts are satisfied and have positive views about this learning aid tool. As an extension of the current work, it would be useful to enhance the heliographic treasure hunt board and clues based on the expert views before being implemented in the actual learning.