The Boston Landmarks Orchestra is happy to announce that the One City Choir will once again perform this summer on our July 31 concert "Deep River."  This concert will showcase African-American music from spirituals to the Broadway stage. There will be songs, excerpts, and narration from Jerome Kern’s 1927 musical Show Boat, which introduced racial themes on Broadway. One City Choir is made up of singers from Boston’s 23 neighborhoods. A panel features Judge Milton Wright and Dr. Emmett G.…