Apokries is the Greek carnival that happens right before Holy Lent, so it changes every year. It is sort of similar to Halloween....but not really. Comparing it to Halloween is really the best way to describe it to someone who is from a country that does not have this celebration. Dressing up in costumes is a practice that dates all the way back to Ancient Greece and was then incorporated to celebrate the Orthodox period before lent. Many different areas of Greece have specific costumes that people will usually dress up as. But for the most part, people can dress up as pretty much anything they want.