But as Brazil grapples with its worst drought in 70 years, the waters have continued to shrink, leaving a stretch of almost a kilometer of sand baking under temperatures of about 40 C.

"Every year it is worse. Last year more than half (of the river) dried up. This year it has dried up almost to the other side," Reis Santos Vieira, a 69-year-old farmer, told AFP.

"And it is expected to get worse," he said.

The Madeira River, a major tributary of the Amazon River that stretches for 3,300 km over Brazil and Bolivia, reached its lowest level this month since monitoring began in 1967, according to the Brazilian geological service.