The events that occurred 20 years ago still reverberate today, despite government efforts to whitewash the incident from history.

Scores of email, photography, and social networking sites are blocked (including blogspot, but there are ways around it).

The square is under tight security.

It's worth reading Nick Kristof's reflections on being an eyewitness 20 years later.

And going back to read his reporting at the time.

[UPDATE] There are some stunning pictures on the Boston Globe's photograph blog.