National Geographic: Elisabeth Leja is 74. She is a retired math teacher who does water aerobics and walks every day for her health. In February, Leja chained herself by the neck to a giant excavator in central Oklahoma that was digging the way for the Gulf Coast segment of the Keystone XL pipeline.
Sitting a few weeks later on a sunny patio at her home in Norman, Oklahoma, Leja said she volunteered for the act of civil disobedience because she believes oil from Canada's tar sands is toxic and a major contributor...