They can also sometimes be found in man-made structures like brick walls.

Climbing can be done in the outside world or inside via man-made structures.

It is often seen on the outside of man-made structures.

It must include man-made structures, and many of these paintings do.

Their nest is an open cup sometimes placed on man-made structures.

There was no trace of any man-made structure in the picture.

When it was out of sight, no other man-made structures followed.

There was only one other man-made structure on the peninsula.

As he stared around, it was hard to say where man-made structure ended and living began.

It, and the castle, were the only man-made structures in view.