Inscrutable

The inscrutable desert was vast and seemingly never-ending.

The inscrutable ocean stretched out endlessly before the sailors.

The inscrutable debate over politics went on for hours with no clear resolution.

The inscrutable amount of sand dunes in the desert made it impossible to tell how far it stretched.

The inscrutable line of ants marched on without pause, seeming to go on forever.

The inscrutable mountain range loomed large in the distance, seeming to have no end.

The inscrutable forest was thick with trees that seemed to go on forever.

The inscrutable queue for the amusement park ride wound around and around, seeming to never end.