If you're considering the Grand Canyon, you definitely want to check out the Glass Walkway thing they opened up recently. You can see it at www.thecanyon.com, which also has maps and answers to lots of questions. I don't know if you've seen anything about it--it's a big horseshoe-shaped thing that sticks out over the edge, and you can walk right out and look straight down through the glass! I live in Colorado, but I haven't actually been there yet myself--I'm not sure if I can handle it or not! smile