In The Lord of the Rings: The Two Towers, Frodo and Sam travel through Mordor.
Mordor is the dark land in the southeast of Middle-earth where Sauron establishes his fortress and gathers his armies. Frodo and Sam approach it with Gollum as their guide, seeking a way to Mount Doom, the only place where the One Ring can be destroyed.
Mordor is not the same place as Isengard, Saruman’s stronghold, or Gondor, the realm whose capital is Minas Tirith. The Two Towers presents Mordor through locations including the Black Gate, the Dead Marshes, and the rocky pass of Cirith Ungol. Its harsh environment reflects Sauron’s military and industrial power.