The life, work and all-round fantastic wonderfulness of author Douglas Adams is being celebrated across the universe today.
The first Towel Day took place on 25 May, 2001 - two weeks after Adams' death - and now his fans mark the event every year, proudly carrying a towel in his honour and taking part in all sorts of Hitchhiker's Guide To The Galaxy-themed events around the world.
So whether you're walking along Edinburgh's Royal Mile in a dressing gown (and carrying a towel and a cup of tea), taking part in London's Vogon Poetry Slam, going along to the Berlin flashmob, or simply raising a glass in honour of Mr Adams today, we wish you all a very happy Towel Day - and leave you with 10 quotes by the man who taught us all we needed to know about life, the universe and everything. The chief lesson among these being, of course, that you should always know where your towel is.
"A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools."
"Flying is learning how to throw yourself at the ground and miss."
"Nothing travels faster than light, with the possible exception of bad news, which follows its own rules"
"I refuse to answer that question on the grounds that I don't know the answer."
"Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so."
"I may not have gone where I intended to go, but I think I have ended up where I intended to be."
"I love deadlines. I like the whooshing sound they make as they fly by."
"I think fish is nice, but then I think that rain is wet, so who am I to judge?"
"I'm spending a year dead for tax reasons."
"Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?"