Tango is easy to recognise: those daring steps, the tight hold of the dancing partners, the intense yet melancholy music dominated by the plaintive sounds of the bandoneon. But if you ask what exactly tango is and where it came from, the answer may not be so immediately clear - because it's more than a genre of music, more than just a style of dance. To get insights into the roots, the culture and even the magic of tango, Rajan Datar is joined by leading tango historians Maria Susana Azzi, Christine Denniston and John Turci-Escobar. Photo: Argentine dancers on stage at the World Tango Championships in 2014 (Getty Images)