One of California's biggest wildfires on record is defying all attempts to halt its relentless charge.

By Tuesday it had burned its way through nearly 73, 000 hectares - that's 180, 000 acres - of land.

Now it's eating its way further into the Yosemite National Park.

It started on August 17th but by late on Monday only about a fifth had been contained.

The cause of the fire is still being investigated.