1. In the beginning God created the Heavens and the Earth.
2. The earth was without form i.e. void; and darkness was on the face of the deep. And the spirit of God was hovering over the face of the waters.
3. Then God said Let there be light and there was light.
4. And God saw the light, that it was good; and God divided the light from the darkness.
5. God called the light Day and the darkness, he called Night. So the evening and the morning were the first day.
6. Then God said Let there be firmament in the midst of the waters and let it divide the waters from the waters.
7. And thus God made the firmament and divided the waters which ere under the firmament from waters which were above the firmament and it was so.
8. And God called the firmament, Heaven; so the evening and the morning were the second day.
9. Then God said Let the waters under the Heaven be gathered together into one place and let the dry land appear and it was so.
10. And God called the dry land, Earth and the gathering together of the waters, he called, seas and God saw that it was good.

Lord Vishnu was lying in Yoga Nidra in the ocean. Two lobes of wax from His ears fell into the ocean and got transformed into two Asuras named Madhu and Kaitaba. They looked around themselves and found no one except Brhma who was seated in the lotus that sprung from Lord Vishnus navel. They charged instinctively towards Him. Finding Vishnu asleep, Brahma appealed to Devi Mahakali, who in the form of Nidra, was keeping Lord Vishnu asleep, to awaken him. (the prayer verses of Brahma are called as Ratrisuktam). Answering to his prayers, Nidradevi moved away from the eyes of Lord Vishnu and He woke up and fought with Madhu and Kaitaba alternatively for five thousand years. He became tired and then He played a trick on the Asuras. He told them that he was very pleased with their warfare and told them to ask for a boon. The Asuras were infuriated and told him that they were stronger than him, it is He who should ask for the boon. Lord Vishnu told them that the only boon he wanted was that they should be killed by Him. Finding themselves thus tricked and also finding that there was nothing but water all round them, they requested Lord Vishnu to kill them in a place where there was no water around. So Lord Vishnu took his Vishwaroopa and showed his expanded thighs which were miles away from the waters and asked the Asuras to lie down on them. They did so and Vishnu killed them with him Chakra.

Their flesh (called Medhas in Sanskrit) got mixed mixed with the waters and formed the Earth. Hence another name for Earth is Medhini. Perhaps the word Urvi (another name for Earth) could have also been derived from the word OORU (referring to Lord Vishnus thighs).

(source: Devi Bhagavatham first skandham)

From the above two legends, we learn that the earth was separated from the waters just as butter is separated curd.

Marduk was the titulory god of the city of Babylone had the power and fame of Babylone grew. His standing in the Babylonian Pantheon also grew until the title of BEL (Lord) was often used to designate him. Marduk was believed to have brought about the creation of the world.

TIAMAT, a terrifying goddess who represented the chaotic, overwhelming ocean was feared by all the gods, except Marduk. At a convocation of the gods, he promised to fight Tiamat and her hated dragons. Out of Tiamats corpse, after he had cut it into two parts, he created Heaven and the Earth; and added the constellations and the planets and fixed their movements. Then on the advice of his father EA, he created man. For his great deed, as well for his magical powers, Marduk was treated as a great god by the other god. (According to a second version, the world was created from the ocean, but peacefully, without a struggle between Tiamat and Marduk).

Marduk was especially considered the compassionate god of the mankind, relieving the mans ills, through the power and the knowledge which his father EA had given him.

Swayambhuva Manu and Shatharoopa prostrated before Lord Brahmadeva and asked Him to tell them what they should do. The elated Brahma told them to procreate children equivalent to them and rule this earth. Manu said I shall obey your orders wholeheartedly, but the earth is submerged in deluge. You must take efforts to bring it out.

Brahma contemplated on Lord Mahavishnu. At that time, from His nostrils, a young pig with the size of a thumb came out. Even while everyone was watching, the small pig enlarged itself to an elephants size.

Brahma with his sons, sage Mareechi and others was very happy. He understood that Bhagwan Narayan has taken the incarnation of VARAHA. He glorified the Lord with vedic chants. The Varaha roared. Hearing the roar, the sages in Janaloka, Tapoloka and Satyaloka were pleased.

The Varaha shook its neck, pierced the ground and was submerged in the flood waters. Vishnu in the Varaha form reached Pathala. He lifted the earth, which was submerged there with him teeth (tusks) and came up. At that time, the great Asura Hiranyaksha obstructed him. After a fierce war Lord Vishnu killed him as a lion would kill an elephant. Then he placed the Earth on its regular orbit.

Varaha was looking reddish, due to the blood of Hiranyaksha smeared all over his body. Brahma and others praised him with Vedic chants. Lord Vishnu was cooled and he disappeared.

Varaha Jayanthi is being celebrated on Chaitra Krishna Chaturthi of every year.

As the deluge occurred during the period between 1,91,81,43,100 B.C. to 1,91,64,63,100 B.C., the Varaha Avathar must have occurred on the fourth day of the 2nd month of 1,91,64,63,100 B.C. as per the Pauranic calendar.

As Varaha protected the earth, Bhoomidevi is treated as his consort. (Narakasura is son born to them). Hence the term Bhoovaraha for this deity who is propitiated for acquiring lands.

The submersion of the earth in the deluge and its extraction seems to recur on a regular cyclic basis as per our Puranas.

Lord Adivaraha after retrieving the earth from the demon Hiranyaksha is believed to have stayed back in earth due to requests of devotees. His two protruding teeth (sort of tusks) fell on the earth with a thud creating two depressions in which water started flowing called Tunga and Bhadra rivers. Similarly in Tirupati, on shores of Swami Pushkarani, there is a temple for Lord Bhuvaraha. Lord Shrinivasa took his permission to reside in Tirupati. Hence, devotees have to first visit Lord Bhuvaraha and then have darshan of Balaji. In South Arcot district of Tamil Nadu a place called Shrimushnam. There a beautiful vigraha is being worshipped. Near Chennai, at Tiruvidandhai Adivaraha is worshipped along with Bhoomidevi. Hence, whenever calamities to the earth occur, we can contemplate the acts of God in reviving the earth to normal position.