This Purple Whimsical Halloween Party Invitation depicts an invitation to a holiday when everyone can indulge in the darker side of life and consume copious amounts of candy. It's a lot of fun, mysterious, and far from serious. However, historically, the holiday was religious and extremely important to the culture of those who observed it. Halloween is always celebrated on October 31 in the United States. Countries that celebrate Halloween the same way as we do, such as Canada, share the same day. However, not everyone is as obsessed with Halloween as Americans are. Halloween is not widely observed in the United Kingdom. This was due to the Protestant Reformation.