On Sunday, a quiet flag-lowering ceremony held in Kabul by the U.S. and NATO was the ceremonial end to a tumultuous and bloody 13-year war in Afghanistan. The event officially marked the transition of the fighting from U.S.-led combat troops to the country’s own security forces, with the expectation being that a relatively small number of American troops will stay on in a few bases in Afghanistan to serve as specialized trainers.

Photojournalist Lucas Jackson has been embedded with the 3rd Calvary Regiment at the operating base Gamberi in the Laghman province of Afghanistan, and in December, he released intimate and up-close photographs documenting the daily life, training, and camaraderie of troops counting down their final days in the region.