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. CullumberAntelope Canyon
© Toby DryeA Photographer's Dream
© Priscilla J. BurgersGods' Light Beam
© Mike W. Detwiler... into the mystic
© Lyn E. Adams