Latvia brands itself as the nation that sings. And with every village and school boasting a choir, it's definitely a place full of harmonies. Less well known is Riga's place in the history of tango. Specifically, that in the melancholy 1930s millions of Europe moved their feet to tunes by a master of the genre named Oskars Stroks. Oskars was born in Daugavpils in 1900, a prodigy in a musical Jewish family. As a teenager he earned much needed cash playing piano in silent movie theatres, which...