Watch this astonishing yet controversial video of 16-month-old Elizabeth Christensen swimming alone in the pool.

Baby Elizabeth swims the length of the pool without any flotation devices or lifeguards. Her parents report that she swims three times a day and can dive in to get toys out of the pool. Elizabeth swims facing downward, using her legs and arms to propel her through the water, and rolls onto her back to catch a breath of air before continuing to paddle. More from Headlines & Global News:

Adam Christensen defended the video clip by explaining to the media that his daughter was trained by a certified professional. "When I first watched her in there, every time she went face down I was like 'oh my goodness, she can't breathe.' I was just worried to death, but the instructor assured us that she was just fine," he told CNN news. "We didn't teach her ourselves. We wanted a professional, somebody that was certified to do that, but we still are able to recognize warning signs, when they're fatigued."

Christensen also wrote in the description of the YouTube video that he is a registered nurse trained in CPR and water safety along with his wife, who is a former life guard. He noted that Elizabeth was trained by an ISR (infant swimming resource) instructor.