Around 75% of the world's population, approximately 4 billion people, don't have an address. Take a country like Mongolia, with a largely nomadic population, where street names and postcodes can be few and far between. But that could all be changing thanks to just three words. Mongolia's Postal Service was the first in the world to sign up to What3Words, an idea from a British former music executive fed up of bands and equipment constantly getting lost. He's divided the entire world into 3m squares and given each one a different three word phrase, and it could mean that everyone in the world will soon have an address. Presenter: Tom Colls Reporter / Producer: Harriet Noble Image: How What Three Words divides up the world / Credit: Google Maps