Over the top is a 3-5 metre high earth covering, from which protrude dozens of ventilation tubes.

Rescuers were able to transfer milk and oxygen to the trapped workers through a ventilation tube until the collapse was penetrated.

Two huge openings at the rear led to well-disguised ventilation tubes on the surface.

This will act as a ventilation tube for the hedgehog.

The Mishnah states that there were 28 ventilation tubes, 14 for each pile, each of which was open at one end only.

Huge ventilation tubes of shiny steel extend the length of the barroom ceiling.

The ventilation tubes were made of brass, and they could be raised or lowered through a special device.

Send poison through their ventilation tubes if not.

Then when the overseer passed, the barrow was rolled so as to flatten the ventilation tube.

Since the ventilation tube was too long, the girl suffocated after several hours.