Every day those who suffer from blindness can often struggle around London's streets.
But the Guide Dogs for the Blind Association, with 2 million pound funding from the People's Postcode Lottery, are helping the blind live normal lives.
The charity are looking to reach out to and support 500,000 people by 2023. We went to the charity headquarters to find out what it takes to become a life-changing dog.
For more information about how to support the charity Guide Dogs, visit their website guidedogs.org.uk