Desolation of the Morannon

The Desolation of the Morannon was the dead land that lay just before walls of Mordor south of the Dagorlad. The terrible barrenness of the landscape was due to the labours of Sauron's slaves, who had so defiled the land that it was diseased beyond repair. It was a foul place of horror for absolutely nothing grew in the polluted soil. Pools of water were choked with ash and muds, slag-mounds of crushed and powered rock abounded, and cones of earth fire-blasted and stained with poison rose as if they were part of a graveyard. 
Frodo and Sam, led by Gollum, reached the Desolation of the Morannon on 4 March, T.A. 3019. The hobbits spent the next day hiding in sight of the Gate, and at dusk they resumed their route.