"I have heard cats from a dozen or more countries play great blues. I think it is almost a universal language" Mark Wenner: Hooked on nails of the Blues The Nighthawks are an American blues and roots band, based in Washington, D.C. The Nighthawks had its genesis when lead singer-harmonica player extraordinaire Mark Wenner returned to his native Washington, D.C., after six years in New York City,…