Treehugger has a timeline that shows how long it would take for traces of human-made things and systems to vanish if we all suddenly went away. Link (Thanks, Phil!)
Reader comment:
Uriel says:
This article in NewScientist describes in detail what the image you posted is showing.
It's a fascinating read, but somewhat dissapointing: It's as if all the things we might want to leave behind will vanish into nature, and all the unitentional and harmful byproducts of our society will remain for ages.