3rd secret to the mystery of Brú na Bóinne Temple

The 3rd secret is about part of what was dis-appeared during the reconstruction for tourism profit. In the lower left of the pic above you can read "Excavated area" - this was a yellow clay bank.  Not locally sourced and its origin is still unknown today. It was roughly due south curving west and then curving north. Half of it still exists. The missing half, if left in situ, would have blocked the fake quartz stone facing that they agreed would make a better tourism attraction. The scientists / archaeology specialists just don't talk about it... Any clay bank can be used as a electrism insulator - it was not a grave = it was an energy temple that is now damaged beyond repair.
The Mortuary House and the Oval Stone are gone. Some time refereed to as the 'hut and the oval; they are simply not there any more and despite their having names their uses are unknown. 

In the above picture you'll see K1 - this is code for the big stone with the multi carvings outside the entrance. Purely as an exercise in measurement - think about how big that stone is and note that it would fit inside the hut or the oval. The oval is roughly twice the length of K1 away from K1. The hut is maybe 5 or 6 times the length of K1 away from K1. 

In the image / plan above you can see the relative size and location of the yellow clay bank. Its end lines up with the direction of the Sun into the temple passage way at winter solstice too... 

Another drawing / plan view showing the yellow clay bank outlined with the hut and oval. Add to this the missing 'arc of pits' that were disappeared while you realise the so called authorities intention was to maximise tourism revenue while treating visitors as dumb cash cows. The missing yellow clay bank allowed the fake quartz wall to be a photographic feature, the disappeared 'hut and oval' increased standing room and the filled in 'arc of pits' stopped questions that would embarrass the money collectors. While you read this be aware of those who present as experts on the temple but never refer to any of these things... instead calling it a grave...

Orientation to the Sun
Back in the 70's excavation era this temple was considered as a huge grave with an interesting aspect to the Sun and not as a solar temple. MJ and Claire O'Kelly who led the excavation and rebuild were insulted in the media by staunch old school types when the couple showed it was a sun temple. WB Yeats an AE Russel had enjoyed an inspired sunrise inside the temple and AE wrote a famous poem about it 70 years earlier. Called "A Dream of Aengus Oge" by George William Russell (who
used the pseudonym Æ or AE). It was published in his 1897 book The Earth Breath and Other Poems and is an interpretation of Aisling Óenguso
But aligned with this solar temple denial is the orientation of these maps / drawings so that the top of the page is not given as north. This means that the alignment to the rising Sun on the shortest day has not been allowed to line up with its true orientation to the world wide celebrated solstice. 3 out of 4 plans do not have the same North arrow and one plan does not even have a North arrow.