As reported by the Baltimore Sun and chronicled in the video below, a K&K Adams demolition crew was performing an emergency demolition on a rowhouse that city inspectors had deemed “unstable.” Everything was going according to plan as the excavator operator worked on the left side of the condemned building, carefully slicing into the structure and picking pieces of it apart.

Around the 48 second mark in the video below is where everything goes wrong. As the excavator’s bucket makes contact with what used to be the third floor of the condemned building, a remaining portion of brick wall on the opposite side of the structure toppled over sideways and directly atop an adjacent rowhouse, immediately bringing most of the building’s second floor to the ground.

According to the Sun, the accidentally demolished rowhouse was “slated to be redeveloped by another owner.” Check out the video below.