Victoria Day seems to only be celebrated in Canada, it's a holiday that most Canadians get off of work and of course celebrates Queen Victoria's Birthday, which was June 20, 1837, the holiday was established after her death, January 22, 1901. She was the daughter of Prince Edward, the 4th son of King George 111.
She inherited the throne at the age of 18 and was respected by the people because of her personal morality. She reigned for 63 years and 7 months, her reign is also known as the 'Victorian Era.'
The holiday is celebrated the Monday before May 25, now a days, a lot of people refer to the holiday as the 'May 2-4 weekend', and is often celebrated with fireworks, spring gardening and bbq-ing - it seems to be the official beginning of summer.