Back at 7:42, with jaw-dropping footage of a great white shark attack. And narrow escapes. And later tonight, you'll see not escapes. Near-misses caught on tape, when swimmers found themselves... See More
Back at 7:42, with jaw-dropping footage of a great white shark attack. And narrow escapes. And later tonight, you'll see not escapes. Near-misses caught on tape, when swimmers found themselves face-to-face with some of the most dangerous predators in the ocean. It's a moment of absolute terror. One that would make almost anyone scared to get back into the water. This footage shows 19-year-old heather boswell facing off with a 14-foot-long great white shark in 1994. I turned around and saw the dorsal fin. Reporter: After a violent battle, boswell breaks free. The shark clampled down anchomped down on my leg. It's all part of shark week, which has bitten off more than 5 million viewers since monday. The shark would bite me. Reporter: Paul is also a shark attack survivor. He was dragged under the water by a 12-foot bull shark in 2009. We popped to the surface. And I took a quick gasp of air. I figured, I'm going to need some air. Reporter: The shark bit through his sweatsuit and eventual his right leg. I felt the real bite. Reporter: This remarkable moment, eric ritter, a shark specialist was attack, just as he said, the sharks were no threat. I realize when she clamped on the second time, it was a pull vit. Reporter: While video is alarming, shark attacks are rare. In 2012, there were only 53 unprovoked shark attacks in the u.S. This year, there's just been 18. Eric was snorkeling on july 29th. I felt this -- on the back of my leg. Reporter: He credits the quick action of his family for his survival. 1 in 11.5 million of us will be attacked by sharks. As these frightening videos show, it's clear why no one wants to be shark bait. Here's the best advice I've ever gotten from a shark expert. Don't act like food, don't smell like good.
This transcript has been automatically generated and may not be 100% accurate.