to break, or cause something to break, into small pieces
The old house’s walls crumbled into a pile of rock and wood.
The old building began to crumble, showing signs of years of neglect.
As the baker sliced into the warm apple pie, the crust began to crumble, revealing the sweet filling.
The sandcastle crumbled as the tide rolled in, erasing the intricate details created by the children.
The hiker accidentally stepped on a weathered rock, causing it to crumble beneath their boot.
