Before arriving in Rio de Janeiro I was convinced that I would never find myself wearing anything smaller than a pair of board shorts whilst at the beach.
Nothing you could have said would have changed that fact; but Brazil proved a formidable catalyst for change in the bathing suit department.
In Brazil (and likely other parts of the world) the swimwear of choice for males is called a sunga.
It is a sort of hybrid resembling the offspring of a speedo and a boxer brief cut.
Yes, it clutches your privates, yes, you feel naked whilst swimming and yes, I bought one my first day in Brazil (when in Rome – “please, go on”).
Typically, board shorts are worn over the sunga on the way to the beach and subsequently removed upon arrival.
Full disclosure: I don't know if I can go back – it is incredibly comfortable.