Saturday's Old Photo

I am declaring--I love declaring things; have you noticed?--that every Saturday is Old Photo Day on this blog. (I love old photos, too; you may have noticed that, as well). Oldest son has been busy scanning and cleaning up some old photos and I might as well make use of them. A nice bonus to this plan is that I'll be able to post something even when I have a busy Saturday, as I often do.

Usually, I'll tell you something about the photo--maybe even a little story about it--but with today's photo, I'm letting you tell me. Put on your detective hat, get out your magnifying glass (Efficient folk will just click for the larger view.) and figure this mystery out.

Where was this photo it taken?

When was this photo taken?

Who is this person?

What is this person doing?

Update: Some of the questions have been answered. The person is me, the time is the summer of 1967 or some year thereabouts. (Check the comments to find out who guessed these things correctly.) No one has pinpointed where the photo was taken or what I was doing. The key is the where of the photo. Once the where is known, the what becomes obvious. I'm not asking the impossible, by the way. Someone will know this place, I'm sure. In fact, if some of the people who have already guessed would pull their thinking caps down a little farther, they would probably come up with the right place.

Update 2: Time for two hints:

1. If you googled for images of this location, you'd get pages and pages of photos of people doing exactly the same thing I am in this photo.
2. The person who gathered the main source material for Longfellow's Song of Hiawatha was at this spot in 1832.
   

Update 3: Jeremy Pierce correctly identified the place as the source of the Mississippi River. That's the spot where the the stream that becomes the river flows out of Lake Itaska in Itaska State Park. The person credited with discovering where the Mississippi starts is Henry Schoolcraft in 1832.

Almost everyone who visits here walks across, either on the rocks or wading through the water, just so they can say they walked across the Mississippi River.