Rolling green hills are fringed by tracts of impenetrable forest.

While on the run, they venture into an impenetrable forest inhabited by a group of cannibalistic witches.

High water forced them up into the almost impenetrable forest.

Just a touch short of oceans and glaciers and impenetrable forests.

At our approach, they scutter into an impenetrable thicket of brambles, nettles and hawthorns, through which a winding circular path has been mown.

My heart sinks on visits to schools where previously some good-natured souls had constructed a wildlife garden, which inevitably grows into an unsightly and impenetrable thicket.

Bamboos form an impenetrable thicket if left untended.

But that only opened my eyes more widely to the experience that others confront as they try to navigate an impenetrable thicket of rules and laws and forms.

The ground in my front was covered by an almost impenetrable thicket.

And yet, the more that you look at his seemingly impenetrable doodles, the more inexorable the pull upon the intellect - and the imagination - becomes.

It can be daunting to start a complaint with a seemingly impenetrable company, but the ombudsman offers guidance even before it can formally step in.

The skill consists in the remorseless application of pressure and leverage as one advances inch by inch through a seemingly impenetrable mass of opponents.

Energy barriers that are seemingly impenetrable to others seem to pose no problem to him.

The film was not an immediate hit among many critics, who faulted its lack of dialogue, slow pacing, and seemingly impenetrable storyline.