Sinking Wall
due to the foundational decay, this wall has begun to sink resulting in it pulling way from the ceiling
Rotten wood
Because the boards have rotted they have begun to cause impressions on each other with the weight of the house
Wood rot
Because of how rotten this wood has become it has begun to break apart
Rot damage
More wood rot which destabilizes the foundation
Rotting wood
even just one beam such as the one in the image being heavily affected will greatly impact the stability of your foundation