At what altitude is atmospheric pressure the greatest?

Atmospheric pressure is greatest at sea level because it is the point where the weight of the air above is the most significant. As altitude increases, the amount of air above decreases. This leads to lower air pressure higher up in the atmosphere, as there are fewer air molecules exerting force downward. Essentially, at sea level, the atmosphere is densest and has the highest pressure, which gradually decreases as one moves to higher altitudes. Therefore, sea level is the point of maximum atmospheric pressure compared to any elevated location such as 500 meters, 1000 meters, or Mount Everest, where the pressure is much lower due to the reduced air column above.