It's the 40th birthday of the postcode.
There are currently 1.8 million postcodes used to cover 29 million addresses across the UK.
But it was actually in Norwich that the postcode was first used, back in 1959, for a trial run.
Now a plaque's been put up in the city to commemorate the anniversary.
Nowadays you wouldn't post a letter without a postcode on the envelope, on average one postcode covers 17 residential addresses.
The post code has also become so much more than just a practical device to help sort our letters.
Now we use them in our sat navs and they determine vitally important things like our insurance, health care provision and our children's school options.
More top news
It is going to be another windy night in store with outbreaks of rain- some heavy at times. Lows of 5 deg C.
Journalist parents from Norwich have received an apology from Tesco after they spotted two mistakes in a packet of baby suits
There's more rain on the way this afternoon and feeling chilly- highs of only 9 degrees C. We'll see more gusty weather tonight.