Here is an excellent link about Zion's famous Subway Slot Canyon
http://climb-utah.com/Zion/subway.htm
I will post the few photos that I have and then have to wait for my sister in law's hi-resolution shots. It is not a casual hike and many unprepared folks have been killed or injured due to carelessness. Properly prepared and guided, you will have quite an adventure.
On Thursday we returned the houseboat and powerboat and raced up to Zion in order to pick up my permit for going into Subway.
The plan was for my s-i-l to start from the top with me and go through the difficult parts. The rest of the group would start from the bottom end and meet in the middle.
After an initial hike that involves some routefinding
we found ourselves at the first obstacle, a rappell over a very large boulder. Here is a shot of my s-i-l coming down the boulder, just as we practiced at Lake Powell
ready for touchdown!