What I think might have happened

The magnificent pyramid was rising and the kings chamber was nearly finished and more rows of blocks had been put in place.

Then in the quiet desert night a huge series of bangs, rang out from inside the pyramid. Camels were hysteric and people from the builders village were woken by the sounds.

The next day an inspection found huge cracks in the pyramid from weight so it became a monument and a smaller pyramid put on top to have less weight with less time and stone used.

This is the bent pyramid of Giza. The builders then started again.