Keywords: 120422-F-TY749-004 (6969622964).jpg U S Air Force 2nd Lt Bryan Humphries assistant officer in charge of the 31st Maintenance Squadron cleans playground equipment at a park in Graf Ignatievo Bulgaria during Thracian Star 2012 April 22 2012 Thracian Star is an annual bilateral training exercise between the U S and Bulgaria designed to provide training and interoperability between the two nations DoD photo by Senior Airman Katherine Windish U S Air Force/Released https //www flickr com/photos/39955793 N07/6969622964/ 120422-F-TY749-004 2012-04-22 08 49 https //www flickr com/people/39955793 N07 U S Department of Defense Current Photos PD-USGov U S Department of Defense Current Photos https //flickr com/photos/39955793 N07/6969622964 2016-09-03 11 43 29 United States Government Work Bulgaria Graf Ignatievo Air Base Thracian Star United States Department of Defense |