The great, silver-sided salmon swirled down and disappeared into an irregularly shaped opening near the bottom of the lake.

Gingerly, he pushed the octagon sideways and revealed a similarly shaped dark opening.

The others followed him through the irregularly shaped opening at the base of the dome.

At the centre of the roof there will be noted a funnel- shaped opening.

The seemingly solid rock in front of him wavered, and then it was gone, revealing an irregularly shaped opening.

Each has a distinct, large irregularly shaped opening near the tip.

On the right is a key hole shaped opening, the function of which is still unknown.

Light spilled in through a series of holes and strangely shaped openings.

They passed through a strangely shaped opening and Helen cried out: "The animals!"

The skull, as restored, features a broad, square, neck frill with two oval shaped openings.