Looking back one, two and five years ago today (give or take a day) on Worldchanging:

2009
Sustainability in Back: Chicago’s Green Alley program
Check out the City of Chicago's Green Alley program, which replaces the typically disregarded back alley with walkways, recreation spaces and even ecosystems ...

2008
Worldchanging and the Green Blogosphere
Worldchanging and other green blogs made Time Magazine's list of the worlds top 15 green sites! Now how about some more love for science-driven sustainable development for poverty alleviation a la SciDevNet?...

2005
Plumpy'nut
James Cascio reports on a new solution for treating malnutrition: Plumpy'nut, a peanut-based paste with the nutritional value of F-100 milk formula...

Other recent "look backs":
April 14
April 15
April 16