The monstrous crimes of war criminals must not be forgotten.
Tips
memory
滔天 literally means 'flooding the heavens' - water rising so high it engulfs the sky. The image extends naturally to crimes so vast they tower over everything. The same 滔天 also appears in 滔天大祸 (huge disaster) and 罪恶滔天 (sins as vast as floodwaters).
