Bunsen Burner Day 
The humble bunsen burner was created by a German Chemist by the name of Robert Wilhelm Eberhard von Bunsen, born March 31st 1811, and Bunsen Burner Day celebrates his birthday.
https://www.daysoftheyear.com/days/bunsen-burner-day/
Eiffel Tower Day
is a holiday that is all about celebrating the wonderful monument that stands proudly in the city of lights. The day marks the completion of the Eiffel Tower in 1889, taking 2 years, 2 months and 5 days in total to build. It was constructed for the International Exhibition of Paris, during the 100th anniversary of the French Revolution, and was named after the principal engineer, Gustave Eiffel.
https://www.daysoftheyear.com/days/eiffel-tower-day/
World Backup Day 
is set aside as a reminder to back up your files, even if it’s once a year! A backup is a reserve copy of all the files you’d be loathe to use. There’s nothing more traumatizing than having losing your phone, or having your hard drive crash, and having hundreds of valuable and irreplaceable documents or photos suddenly gone beyond retrieval.
https://www.daysoftheyear.com/days/world-backup-day/
Crayola Crayon Day Crayola began its life as a company when cousins Edwin Binney and C. Harold Smith took over a pigment business in 1885 that Edwin’s father owned. Since then, they have produced a core set of 120 crayon colours; but they have also come out with many unique sets; including metallic coloured crayons, gem tones colours, and even scented ones.
https://www.daysoftheyear.com/days/crayola-crayon-day/
http://www.famousbirthdays.com/march31.html