U.S. Soldiers from 317th Brigade Engineer Battalion, 3rd Brigade Combat Team, 10th Mountain Division (Light Infantry), participate in chemical, biological, radiological, and nuclear (CBRN) defense training with the Bulgarian Army at Novo Selo Training Area, Bulgaria, Sept. 26, 2024. Joint CBRN training is essential for enhancing collective readiness, ensuring interoperability, and effectively responding to chemical, biological, radiological, and nuclear threats. (U.S. Army video by Spc. Alexcia Rupert)