Firefighters are still battling the last of the bushfires which swept through the state of Victoria in south-eastern Australia.
More than 180 people were killed and whole towns wiped out, in what's been called one of the worst natural disasters in the country's history.
So what has caused them?
Wildfires are blazes which break out in areas like forests or other wildlands.
They happen in lots of countries across the world, and in Australia they're usually called bushfires.
Lots of places there are hot and dry, and some of the plants - like eucalyptus forests - catch fire very easily.
Bushfires can be caused by lightning strikes, but they can also be caused by people being careless, or even starting them deliberately, which is called arson.
It's thought that at least some of Australia's recent fires were deliberately started and one man has been charged with starting a fire on purpose.
A huge police investigation is under way, but so far no-one knows who is responsible, or why they would have done it.
And there are other reasons why the fires were the worst people in Australia have ever seen.
In recent weeks, parts of the country have been sweltering in a heatwave.
The high temperatures, along with a lack of rain, made the forests even hotter and drier than usual - so it was easy for the fires to take hold.
To make things even worse, the wind kept changing direction, fanning the flames all over the place.
The weather has taken a turn for the better, with temperatures dropping and even some rain falling.
But days after the worst of the blazes, firefighters are still battling to bring the last of them under control.