Col. Nikolay Lyaskovski, head of Force Protection in the Branch of Training Department for the Bulgarian Air Force, examines a night vision lens on May 31, 2017 at Berry Field Air National Guard Base, Nashville, Tenn. Tennessee partners with Bulgaria under the State Partnership Program, which is designed to train allied forces, build international relationships, and enhance regional security.

- Image ID: R6N2K0
Col. Nikolay Lyaskovski, head of Force Protection in the Branch of Training Department for the Bulgarian Air Force, examines a night vision lens on May 31, 2017 at Berry Field Air National Guard Base, Nashville, Tenn. Tennessee partners with Bulgaria under the State Partnership Program, which is designed to train allied forces, build international relationships, and enhance regional security.
Ted Small / Alamy Stock Photo
Image ID: R6N2K0