Artists Marina Abramovic and Ulay started an intensive love affair in the 1970s, performing out of a van they called home. When they ended their relationship, they decided to walk the Great Wall of China, each from one end, meeting for one last embrace in the middle. That was the last time they saw each other. In 2010, as part of a MoMA retrospective, “The Artist is Present”, Marina shared a minute of silence with each stranger who sat in front of her. On opening night, Ulay arrived without Marina knowing….