Yoshitaka Yamaguchi, 374th Civil Engineer Squadron environmental engineer, gives a wildlife presentation, during an eco tour of the Tama Hills Recreation Area, Japan, Oct 23, 2019. Engineers with the 374th CES lead eco tours each year for citizens of Inagi City, which surround the recreation area. The site, a former Japanese Imperial Army munitions processing and storage plant, was so well concealed by the surrounding terrain that it remained undetected by Allied forces throughout World War II. Officials maintain the site's biodiversity and have also erected historical plaques throughout the 250-acre site containing bunkers, foundations and tunnels. (U.S. Air Force photo by Yasuo Osakabe)