See this gallery of caverns, cave picturess and canyons. Also, don't miss this BetterPhoto article on digital exposure camera techniques.
Light at the End of the Tunnel
© MARLON IGNACIOAntelope Canyon
© Sue L. CullumberInside Bryce
© Ken SmithAntelope Canyon
© Toby DryeRainbow Canyon
© Kelvin S. MurphyA Photographer's Dream
© Priscilla J. Burgers