April 15 marks China's sixth National Security Education Day. The Hong Kong and Macao special administrative regions marked the occasion with various activities. Carrie Lam, chief executive of China's Hong Kong Special Administrative Region (HKSAR), Luo Huining, director of the Liaison Office of the Central People's Government in the HKSAR, and Yang Yirui, acting commissioner of the Chinese Foreign Ministry in the HKSAR, on Thursday attended a ceremony marking the day and delivered speeches. Check out the video for more.