I can't remember the movie, but it had Charlton Heston as the pyramid builder and ummmmmm that King and I guy as the pharoh ?????? and the whole thing about this was building the Cheops pyramid and then setting off all the intricate internal locking and sealing mechanisms...
Now the kings wife was a schemer, who wanted to get it all when he died... and
The really scarey bit was the locking and sealing mechanism, which included the kings family and priests, all being seated in a sealed room inside the pyramid, and a HUGE rectangular stone block slide down an internal ramp, breaking off these clay cups, in the walls.
As the clay cups broke, sand came pouring of the chambers behind them, and flowed down the slop and into some channels, that excited into the room where the queen and priests were... effectively and eventually, burying them alive inside it.
The queen was rather non plussed when she discovered that she had in fact inherited the kingdom - his after life one, and that she got to join him in it - for eternity.
And I look at all these concrete bunkers and underground chambers, and I think, "Well - these are all just underground tombs.... - and I hope to die, in the middle of a green grassy field under some nice trees."