"The BFG," "The Twits," "Charlie and the Chocolate Factory," and "Matilda" are just some of the hugely popular children's books by the British author Roald Dahl, born on September 13, 1916. To celebrate the writer's 100th birthday and his contribution to literature, festivities have been occurring around the world, with many more to come for the day itself.

Having sold an estimated 200 million books, Roald Dahl, who passed away in 1990, is one of the most successful children's writers in history. Prior to his decision to write for a young audience, he penned many popular adult stories. To celebrate the centenary of his birth, Dahl fans of all ages have been organizing events from face painting in Wales to garden parties in the US.

"The World's Number One Storyteller"

The Penguin Young Readers imprint and the Roald Dahl Literary Estate have collaborated to organize events across the world. The publisher will release new collectible hardcover formats of some of the writer's most popular stories on September 6, when US-based fans will also be able to purchase copies of Roald Dahl's moving letters to his mother, entitled "Love from Boy", from Blue Rider Press. September will also see the publication of the Oxford Roald Dahl Dictionary for childen aged 8+, full of over 8000 words that Dahl created.

On September 13 itself, the U.K. will celebrate #RoaldDahlDay2016 with the "Puffin Virtually Live: Roald Dahl Show," a free webcast including a performance by the cast of "Matilda, the Musical," interactive games and a peek behind the scenes of Steven Spielberg's blockbuster "The BFG."

In the U.S., where Dahl wrote two of his most successful books "James and the Giant Peach" and "Charlie and the Chocolate Factory," his birthday will be celebrated in bookstores, librairies, classrooms, gardens and open public spaces across the country, culminating on the weekend of September 17. Steven Spielberg's movie adaption of "The BFG" came to theaters in July, and screenings of "Willy Wonka and the Chocolate Factory" are taking place all over the US throughout the fall season.

In Wales, where Dahl was born, one of the celebrations includes the ongoing Quentin Blake "Inside Stories" exhibition, running until November 20, 2016. Blake was the famous illustrator who brought Dahl's characters to life.The interactive exhibition "The Wondercrump World of Roald Dahl" is moving from its London Southbank location to the Wales Millennium Centre until January 2017. The Roald Dahl Museum itself, in Buckinghamshire, England, is also hosting a full agenda of activities and events to celebrate the day through October.

Other countries honouring the centenary include Malaysia, China, Thailand, South Africa and more.