Nearly two years have past, and families throughout China still don't know what happened to their loved ones.

Wednesday marks the second anniversary of China's worst disaster in a generation, the Sichuan earthquake -- and a painful milestone for the families of the 17,921 people still recorded as missing.

Chinese law says relatives can apply two years after a disaster to have their loved ones registered among the dead. Not many are expected to do so. It's a choice that offers some minor financial compensation and a mix of closure and fresh pain.