The thing about the past is...

It's not stagnant. Much like history, which is written by the victors, it changes with time and circumstance. It's vulnerable to alteration, and manipulation, and if not for the efforts of the vigilant and valiant, it can disappear like smoke.

I'm reading two books about China that came out over the past year -- I wanted to read them this summer and would have if not for the Olympics -- and I'm struck by two separate but related passages:

Peter Hessler, Oracle Bones:

The [Nanjing Massacre] memorial featured signs in Chinese, English, and Japanese:

DON'T FORGET HISTORY

THE PAST KEPT IN MIND IS A GUIDE TO
THE FUTURE

Philip Pan, Out of Mao's Shadow:

There were dozens of other graveyards with victims of the Cultural Revolution scattered across Chongqing. The party demolished them all after Mao's death. The cemetery in Shapingba Park has survived, Zeng said, but the government "wants it to erode and deteriorate naturally. It wants people to forget about what happened. But I think it would be a tremendous loss if this history were forgotten, because it was cast in the blood and tears of the Chinese people. Furture generations must learn these lessons so tragedies like this don't happen again.

"In the future, when people visit this cemeery, the words on the tombstones won't be visible anymore," he added. "I hope my written record can fill in the blanks."