The Dwarven Catacombs, a nice area with a cool puzzle, for lowish level players.

Walk ( 8e, 2se, s, 3se, e, 2ne, n, 2ne, n, nw, n, ne, w, push/pull leaves, 2e, 2n, 2u, open u, u, open u, u, e, 2d, 4n, open n, n, open n, n, d ) to get from DH to the room marked in blue.