The small Mexican town of San Juan de la Vega has been throwing a bizarre annual festival for centuries, and its exploding in popularity. Festival participants attach a mixture of sulphur and chlorate to the end of sledge hammers and then smash them against rail beams, exploding the substance into huge clouds of smoke. More and more people are making their way to San Juan de la Vega to see the baffling festival of the exploding sledgehammers.