Hong Kong Police marching band performs during an open day to celebrate the National Security Education Day at the Hong Kong Police College in Hong Kong, China

police marching band music marching band music marching band playing music band performing national security day nsd event national security event chinese national security police training day counter terrorism training counter terrorism event visitors attending hong kong police chinese police propolice event prochina government government supporters chinese visitors chinese attendees attendees supporters hongkongers series academy traning china patriotism hong kong social issues violence exposed generational violence exercise celebration open day open to public watchers patrotism patriotic exercise stadium show marching white uniforms performing playing music concert live concert