Most days in each year are associated with a Saint. Many Saints are associated with objects, jobs places etc. as their Patron. Regardless of your views on religion, these Saint Days are a good reason to go and celebrate something each year.
Today is St. Patrick's Day and St Patrick is the Patron Saint of Engineers... who knew that?! Now that you do, then 17th March is a good excuse to celebrate some Engineer or Engineering feat.
Back in the day, St Patrick went over to Ireland from England to do God's work, stopping off at Glastonbury Tor to bury the Holy Grail. As a Roman educated Englishman who had travelled around Europe he had a good understanding of modern technologies that were unknown in Ireland. Things like building walls with lime mortar instead of dry walls, using arches to make big doors and windows, and introducing ceramics such as artistic tiles. Of course, his job while over there was to introduce Christianity to the Irish which he did by building churches so those skills came in very handy.
There appear to be two possible reasons for the association of St Patrick as the Patron Saint of Engineers.
St Patrick was well known as a ground-breaking Engineer in Ireland about 1500 years ago. In more recent times, lots of Irish people spread around the world, and became as a nationality, synonymous with Engineering in many ways. They built railways, tunnels, and developed new technologies all over the world. Engineering became linked to the Irish and the Irish are linked to St Patrick.
Another theory is that early 20th Century university Engineering students in The USA discovered this potential for a link and persuaded their universities to give them a cheeky day-off to celebrate.
It doesn't really matter why, the 17th March is an internationally recognised excuse to celebrate some engineering feat. Go checkout Crossrail - one of the world's largest current projects here in the UK. Have a look at the London Array - the world's largest wind farm (when built by the amusingly-titled DONG Energy and others) just 12 miles off the coast near us in The Geekery. Celebrate the 30th birthday of ARM, one of the UK's most successful innovative companies, with products in most if not every single mobile phone out there. It's truly amazing.
We in the UK should celebrate our engineering more. We led the world in the 5th century and still lead the world today. We don't really talk about it and that needs to change. Please let us know what your favourite engineering awesomes from the UK are in the comments below.
References
First image taken from https://online-engineering.case.edu/blog/the-story-of-st-patrick-the-engineer