In 1970, the first Earth Day was celebrated with a series of fairly mild protests focused on environmental issues. Here's what happened in three cities, according to CBS News.
The first Earth Day "Die-In" at Logan Airport was peaceful (if a bit bleak), but the state police broke it up anyway. Yikes:
Let's see what kept the sun from shining in on Philadelphia. There's more on this and the New York City events at Wikipedia.
New York City
Sweeping Union Square! And kids "participating in their very first demonstration."
The Whole Special
The three segments above are taken from a CBS News special anchored by Walter Cronkite. Here's the whole thing, in an hour-long playlist: