On April 21 2007 NASA's Astronomy Picture Of the Day site featured an anaglyph of the "face on Mars".

Included in the caption is an explanation of some of the mechanics of anaglyphic photography,
including a link to a site which explains how anaglyphs work.

So, where does NASA turn for accurate and well-presented technical information?
faxmentis.org, of course.

APOD 21 April 2007
The first time NASA linked to us.

faxmentis.org explains anaglyphs

Break out of this frame.