Peru has sent the security forces to destroy river dredgers used by illegal gold miners in the country's south-eastern Amazon region of Madre de Dios.
Nearly 1,000 troops and police officers took part in the operation to destroy the miners' main tools.
Seven of the boats which suck up silt from the riverbed were sunk or burnt.
Officials say the mining produces up to 18 tons of gold a year and causes immense destruction to one of the most biodiverse places on earth.
The operation was an important first blow against illegal gold mining in Peru.
On a good day, the river dredgers can find almost $30,000 (£18,000) worth of gold, yet the miners pay nothing to the state.
But the true impact of Peru's Amazon gold mining goes beyond hundreds of millions of dollars in unpaid taxes.
Poisoned food chain
For every gram of gold, up to three times more mercury is used to extract it.
It is estimated that annually more than 40 tons of the toxic metal are absorbed into the air and rivers of Madre de Dios, poisoning the food chain.
Fish in the area contain three times more mercury than is safely permitted by the World Health Organization.
Sky-high gold prices have enticed migrants from Peru's poor highlands into the region to mine for the precious metal.
They are turning huge swathes of rainforest into desert.
The illicit cash and lawlessness also create social problems.
Child prostitution, for instance, as well as indentured labour, drug-trafficking and money laundering.
Environmentalists blame the Peruvian state for years of inertia in combating illegal mining in the region.
That may now be changing as the authorities say they plan to destroy hundreds more illegal mining operations.