It was exactly 40 years ago that the musical revolution that came to be known as Tropicalia was introduced to Brazil, and the world. 

Tropicalia's genesis can be dated with some precision. It came when two musicians in their mid-20s, Caetano Veloso and Gilberto Gil, courageously took to the stage at a 1967 song festival in Sمo Paulo with compositions that they knew would sorely stress the boundaries of musical taste. Their performance was epoch-defining. It was a kind of big bang from which much that came afterward in Brazilian pop music history evolved.