One of the main reasons to visit Katmai National Park is because of its large population of Alaska Brown Bears. Genetically these are essentially identical to grizzly bears, but they have a diet rich in salmon and grow to a huge size -- much larger than an inland grizzly bear.
My wife and I spent an amazing week in Katmai, going on daily tours in search of bears. We saw a lot of them, none bigger than this one. It was a huge male which our guides estimated at about 750 pounds (brown bears can get much larger than this). But summer was not over yet and they expected he'd get much heavier before he began his hibernation.
We studied this particular bear for about a half hour, watching him fish, catch and eat several salmon, and wander around.
At one point he came to within 10 feet of our group, and we got to see him up close. He was aware of us but made no threatening gestures and just passed by.
The following video gives you a better look at the bear: