The chain was over three countries, 600 kilometers and two million people long and foreshadowed the region's eventual independence two years later. Recent echos of this have been felt in the country of Georgia where residents formed a chain of about a million people to protest Russia's attempt to split the country in two.
That later one brought 17,000 people out. One of many complaints residents have against the base is the pollution caused by air traffic. Protesters made another human chain around a US military base in Guam in 2010 when the Marines suggested turning a historically and biologically significant site - Pagat - into a firing range and training area.
Nairobi Greenline, is also planning to plant nearly a million native trees around the park.
decided to phase out nuclear power months later (for an interesting contrast, check out this human chain in support of nuclear energy in Iran in 2006 - state approved, of course). Similar protests have been held in France, where nuclear power makes up the bulk of the country's energy supply.
2 kilometer-long human chain ("No hay dignidad sin Justicia" - There is no Dignity without Justice) in San Salvador this July to call attention to the poverty and poor housing conditions faced by many in the city. Here's a video.
Here's another list that focuses less on environmental issues.