Here are this year's smokin' hot contestants for Brazil's Miss BumBum competition marching together for ... something ... we're sure ... but you don't care.

What really matters is the 27 hopefuls kicked off the competition by showing off their (potentially) award-winning asses, all in unison. This year there's an amputee in the running, and based on these pics she's got a good shot at the prize.

This is an annual tradition in Sao Paulo and, besides Carnival ... it might be Brazil's greatest export!