Buckner was again cited for gallant conduct at the Battle of Molino del Rey, and was appointed a brevet captain. He participated in the Battle of Chapultepec, the Battle of Belen Gate, and the storming of Mexico City. At the conclusion of the war, American soldiers served as an army of occupation, which left them time for leisure activities. Buckner joined the Aztec Club, and in April 1848 was a part of the successful expedition of Popocatépetl, a volcano southeast of Mexico City. Buckner was accorded the honor of lowering the American flag over Mexico City for the last time during the occupation.