One of California's biggest wildfires on record is defying all attempts to halt its relentless charge.<br/> <br />By Tuesday it had burned its way through nearly 73, 000 hectares - that's 180, 000 acres - of land.<br/> <br />Now it's eating its way further into the Yosemite National Park.<br/> <br />It started on August 17th but by late on Monday only about a fifth had been contained.<br/> <br />The cause of the fire is still being investigated.
