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

2009
AUTO. SUEÑO Y MATERIA - Cars And Landscapes
Regine Debatty reviews an exhibition at Laboral Centro de Arte y Creación Industrial, which analyzes contemporary car culture through the lens of some 100 artworks...

2008
"B" is for Beneficial: The B Corporation
To help companies maintain their morals in the face of corporate takeovers, and to attract socially responsible investors and consumers, a nonprofit called B Lab has created B Corporation, where the 'B' stands for beneficial (to the business, public and environment). Read more about the B Corporation certification...

2005
Return of Sonofusion
James Cascio explores the state of Sonofusion research. By 2050, we could be living in a world powered by wind, the Sun, and stars in a jar...

Other recent "look backs":
May 19
May 20
May 21