Greek religious beliefs
The Greeks thought that the Gods were almighty beings, who would punish them if they did not please the Gods, but would reward them with things within their powers. They also feared they would be punished if they worshipped one God above the others, so they came up with a solution. They had one temple for each god, and each temple had a priest or a priestess. Committing crime, or undergoing sexual activity within the temple was punishable by torture, before death. However you did not go to the temple to pray or worship, as the temples were the homes of the gods. Within each temple, their would be an altar, where they would take up animal sacrifices for the gods to please them. The priests and priestesses of the temples worked on keeping the temples clean, and making sacrifices, while the oracles communicated with the gods, and asked questions for the people, and received prophecies. The priests were only dedicated to one God, and pledged their loyalty to that God before taking up the role of priest. The people worshipped the God by praising them at temples, although not often, by making sacrifices for them, and giving them gifts, and by carving and creating statues or artworks of the Gods. If they did make something, or give a sacrifice, they would then give it to the priest who would either place it decoratively, or take it to the altar.
The Gods the Greeks worshipped were significant in numbers, with the twelve main Olympians, and the "Big Three" brothers, Zeus, Poseidon, and Hades. Zeus, was the overall king of the gods, and god of lightning and thnder himself, Poseidon was the god of the sea, and other marine thing, and Hades was the king of the underworld. They each ruled a different part of the earth, Zeus controlling the sky, Poseidon controlling the ocean and lakes, and Hades controlling the underworld. The earth belonged to the titan Gaia, who was the mother of Cronus and the grandmother of Zeus. You can find out more about all of the gods, including their powers, in the Gods/heroes page.
Most marriages and childbirths had very little to do with religion in Greek culture, although they did have gods and goddess's of love, marriage and childbirth. It is however known that sometimes they would make a sacrifice to wish them luck with their marriage, or something else small.
Overall the Greeks had a massive religion, with many complex myths, heroes, and gods. They also had many insane stories to explain how things came to be, such as stories you might hear today, such as how the elephant got its trunk, or how the turtle got its shell.