Spark plug with ground electrode in a recess on housing end side

A spark plug with a longitudinal axis, comprising:

• a housing with a hole along the spark plug longitudinal axis and a combustion-chamber-side end side, wherein the housing has a recess on the combustion-chamber-side end side of the housing;
• an insulator arranged inside the housing;
• a central electrode arranged inside the insulator;
• and
• a ground electrode arranged in the recess on the combustion-chamber-side end side of the housing;
• wherein the ground electrode and the central electrode are arranged such that an ignition gap is formed within the housing,
• wherein the recess extends from the combustion-chamber-side end side of the housing towards the housing end facing away from the combustion chamber,
• wherein the ground electrode is located at the lowest point of the recess,
• wherein the recess has a depth such that the ignition gap is arranged entirely within the housing, and wherein neither the central electrode nor the ground electrode protrudes into the combustion chamber.