Inside the Great Pyramid square ducts, 20 cm x 20cm, named aeration ducts, have been discovered.

Two are in the north and south wall of the King's Chamber.

They cross the granite wall of the Chamber lengthways, then go up.

The south duct has a straight path; on the contrary, the north one bends, at the beginning,  to the west side to avoid the intersection with the grand gallery.

The slope gradient is not the same for the two ducts, but, due to the starting point asymmetry, they go out at the same level At the same time  the transversal section area becomes bigger and bigger while going up, until to get  9 times the lowest one.

It was not difficult to find them because they are visible inside the chamber. On the contrary it was more difficult to find the external outlets.

Two additional similar ducts, also in the size, have been found in the Queen's Chamber, but  they had no visible outlets, which had been hided by a small stone screen (about 10 cm thickness) belonging to the wall limestone block itself.

They had been found in 1872 by Waynman Dixon, following an acoustic test. The thin limestone screens had been removed quickly by hammer and chisel.

Also in this case they go up, the  north one still bending, with the same slope gradient, as they have to go out at the same pyramid level. Unfortunately these outlets, if existing, had never been found yet.

Furthermore the Queen's Chamber ducts have a singular unexplained characteristic. Rudolph Gantenbrink, using a small ingenious robot, found the two ducts are closed, after a path of 65 mt., by a limestone screen, showing in the upper and central position a couple of poor copper handles.

These “ handles ” go out from the stone as per an improbable duct visitor (picture 1).

The two stone plugs of these ducts, upper and lower, caused the curiosity of many people, including me.

Hoping the ducts were connected to a secret chamber, on September 2003, a second robot has been sent inside;  hole drilled in the stone screen. A micro-camera showed beyond that just another  rough stone plug , without any handle, closing the duct at  a distance of 21 cm only from the first one, which shape, on the contrary, look like it had to be slightly inserted in the previous one.

I still remember my disappoint knowing that, but, later on, I had a logical idea, even if disputable:

I show you that.

Imaging who drew up the project (and I’m convinced there was just one) decided, for unknown reasons, the ducts have to be hided later so that none, finding the external outlets and knowing their slope gradient, could never guess the secret chamber position.

He didn’t close just the external outlets by a stone screen, but, probably, he wanted to fill the last part of the ducts by a stone block convoy.

So he planned the ducts having two sections of different size.

Starting from the Queen's Chamber, the ducts go up, having the smallest section area, up to 65 m. from the entrance; then they change suddenly, doubling their square side, up to the external outlet.

The connection between the two duct sections is the same we found in the King chamber, having no step at the bottom side (see picture 2)

When it had been decided to close the duct, the first stone had to have a particular shape  like a self-centring device to seal the duct in a proper way (nothing had to enter in the duct).

This particular stone had to have two holes in the centre, 7 or 8 cm distance in between. A copper bracket had to be inserted in the holes to form an eye at the upper side for a rope fastening. At the opposite side, the bracket ends had to be hammered against the stone, taking the shape we know (see picture 3).

At this time a double rope had to be inserted in the copper eye as the stone dropping down, checking the stone position in the duct by the rope itself.

As the stone inserted in a manner to have a proper seal, the rope had to be removed and the upper duct filled by more stone blocks, certainly a little bit smaller in dimension, to allow a good slipping.

The first filling block, going down the duct, hurt fiercely the copper eye.

The copper eye shall be driven into the stone moving out, at the stone opposite side, the bracket ends, hammered before.

Imaging now to watch the stone from that side, like the robot camera did.

We will see a stone having two strange copper handles in the centre……(picture 4).

Efrem Piccin