The protest was attended by thousands of people against the building of a natural gas line line through the city. (The story can be read at: http://www.nytimes.com/2011/10/22/us/puerto-ricos-plan-for-gas-pipeline-has-many-critics.html?pagewanted=all.)
Locals told us that although they supported green energy, they felt that this project was rushed, not well planned, and posed a health threat for the communities where the gas line was being built.
We hear ya Puerto Rico!
Even more impressive than the size of the protest and people's commitment to the cause, was their commitment to having fun while they were doing this work.