From damming rivers to changing the chemistry of the atmosphere, humans have had a powerful impact on our planet.
But what would happen if we suddenly disappeared?
The first few weeks would be chaotic.
Within hours, power plants would run out of fuel and shut down.
As lights go out and electric fences lose their sting, over one and a half billion cows, nearly a billion pigs and more than 20 billion chickens will break out of their enclosures, desperate for food.
Without any humans to feed them, most of these livestock will starve or become food for over half a billion dogs and a roughly equal number of cats who now have to fend for themselves.
Of course, many of our fancy breeds are ill-suited for life in the wild, and will probably be outcompeted by hardier mutts, not to mention wolves, coyotes and wildcats.
Other animals that depend on humans, from rats to cockroaches, will suffer drastic population declines.
Some, like body lice and head lice, will go extinct.
In the cities, many of our famous boulevards are now rivers.
