No, I don't know how she got up there, but she was swinging her baby in the air screaming like a madwoman. I grabbed the camera, took a few pictures and promptly got her down, told her "no," and sat her in the corner. Not 5 minutes later, as she and I were playing, she tried to climb up there again. Argh.
Follow-up story . . . I guess yesterday I finally got through to Avery that she couldn't climb on her shelves. I guess I need to be more clear for the toddler who is clearly testing her limits. Today she was using it as a chair. Less dangerous I guess . . .