Many serious nature photographers from all over the world know about this place and let me tell you, a whole lot of them make the pilgrimage to get here every year. It's the Mecca of slot canyons and unfortunately gets quite crowded most days. It lies on Navajo Indian land, so you need to hire one of the several guide services that share rights to bring people in here. They will transport you from the little nearby town of Page, right up to the opening that you see here in the middle pic, then take you on through for a certain amount of time, depending on the tour you purchase. If you want to do any serious photography, you'll need to pay a little more for the 2 1/2 hour photo session that most of the guides offer. That will give you, besides enough time to work, a referee of sorts for your limited size group, and they will at least try to keep the other groups separated and out of your way in each of several good spots. The guide for my group even played an indian flute for us while inside to enhance the mood. Even so, you will need to be patient and a bit aggressive to get the good angles. Fortunately, the exposures in here are quite long, so even if someone walks through your shot while your shutter is open, (and they will) they'll show up little if at all. Sometimes the "ghost" effect is even kind of cool. Some of the more casual tourists are not too concerned about kicking up dust as they shuffle about, either.
I believe they used to let people in here by themselves after paying a fee, but it got too crowded to manage that way and also there is the danger of flash flooding. Rain so far away that you don't even know it's falling can rush through here suddenly and it's all over if you happen to be inside, so they are careful about watching the weather. In 1997, eleven tourists from France, Sweden and the U.K. were caught in the lower Antelope Canyon and drowned. One somehow managed to survive.
The upper, vertical shot is taken from outside, right at the entrance and you can see some people with their point and shoot cameras.. once again, good for scale reference, although it gets much larger inside. Some spots are comfortably wide, others are very narrow, so hopefully you don't have claustrophobia! The larger, third image is actually far from one of my best from this shoot, but I think it is reasonably good at expressing what it's like inside this mysterious place. If you're lucky, you'll catch a sunbeam shining down from above onto the floor!