Religious holidays
Holidays connected with religions are the most widespread type of holidays and probably the oldest ones existing on Earth. Since ancient times people around the globe believed in different Gods irrespective of the number of their population, their cultural development, social organization etc. It is in the human nature to believe in divine forces that govern all processes going on in our lives. That's why people always tried to gain the favor of the gods they believed in, irrespective of their religion, in order to receive various benefits like good harvest or weather, wealth, health, power, dominance or whatever humans have always been striving for. For this reason, as ancient people thought (and still think), various sacrifices need to be made for the gods in order to make them give you what you want. The sacrificing customs and traditions gradually developed into more complicated phenomena that acquired the signs of modern holidays and festivities - as people sacrificed killed animals, for example, they ate them right after the rituals. This is where most such holidays originate from. Later on, as mythologies of separate nations developed and social and cultural systems became more and more complicated, new occasions for celebrations or observances appeared that had to be implicitly observed – which is the same today in countries with high level of impact of religion on the society in general. Thus holidays connected with specific events in history (or mythology) were established (for example Christmas, Easter, Hanukah etc).