Mordor. No really.
The place looks like Mount Doom, or maybe Mars, and it is certainly many miles from the Shire. It is formidable both from the areal view and at ground level. There are hardly any green things growing, just the occasional masochistic daisies, and the ground is crunchy hard lava waiting to collapse on you should you happen to walk over a once forgotten terrestrial lair. The lava comes in two forms. Smoothish ribbons that you can picture flowing at thousands of degrees, red hot, covering anything in their path. And then there is the other stuff. The sharp knives of pumice that perhaps cooled faster (or is it slower, I don't know my geology that well) and these guys, they are out to get you. You should avoid them at all costs, walk around these ominous patches, take a detour if you must, sharp rocks are not your friend.