When: April 23rd every year (unless you’re a Brit, then it’s the first Thursday of March)

Who: It’s organised by UNESCO

Why: Promotion of reading, publishing and copyright

Where: Around the world! But it started in Catalonia.

This year, the World Book Capital is Athens in Greece. Every year, a city is chosen for the role until the next 23rd April.

The first official Day was celebrated in 1995 and the World Book Capital City has been a feature since 2000.

You can find out loads more by looking it up here.