Earthwalker

Prerequisite: 21st level, Born of the Elements feat
Benefit: You gain earth walk, meaning that you ignore difficult terrain caused by rubble, uneven stone, or earthen construction.
    In addition, whenever you use your second wind, you have phasing until the end of your next turn. Using this feat, you can phase only through earth and rock.

Published in Heroes of the Elemental Chaos, page(s) 143.