This Boulder group that performs with only their voices or, a cappella, is bringing a holiday show to Denver. Their show is a musical journey that starts in the 12th and 13th century with songs like “Ave Maria.” Taking the audience all the way to the 19th century, the 36 singers, will sing early American carols. Special guest, Lucille Reilly, will join them on stage as they perform a beautiful holiday show put together by artistic director, Thomas Edward Morgan. Days, times vary.