“‘Follow me!’ said Merry […] He turned to the left along the Hedge, and soon they came to a point where it bent inwards, running along the lip of a hollow. A cutting had been made, at some distance from the Hedge, and went sloping gently down into the ground. It had walls of brick at the sides, which rose steadily, until suddenly they arched over and formed a tunnel that dived deep under the Hedge and came out in the hollow on the other side.” — Chapter 6: The Old Forest, The Fellowship of the Ring
The dreaded entrance to the Old Forest. I personally hate the zone, but I guess you’re not supposed to easily find your way around it ;)