"And God said, 'Let the waters under the heavens be gathered together into one place, and let the dry land appear.' And it was so. God called the dry land Earth, and the waters that were gathered together he called Seas. And God saw that it was good."
"And God said, 'Let the earth sprout vegetation, plants yielding seed, and fruit trees bearing fruit in which is their seed, each according to its kind, on the earth.' And it was so. The earth brought forth vegetation, plants yielding seed according to their own kinds, and trees bearing fruit in which is their seed, each according to its kind. And God saw that it was good. And there was evening and there was morning, the third day."
This is the Biblical account of the third day of the world. Land was formed, as mountains and hills jutted out of the ground, while valleys and prairies fell at their feet. Water rushed around the world filling river beds, lakes, seas and oceans, separating the salt water from the fresh water. The Creator who needs no land or water to walk on created land and water for us to walk on so we could walk with Him.
The third day was the first day of life. Plants and vegetation sprouted out of the ground for the first time in preparation for what was to come next. Fruits, vegetables, seeds and plants took over the earth in preparation for the provision it would soon have to provide for all living creatures, and flowers and trees clothed it in matchless beauty.
An invisible Creator created the visible, and the Provider of all provided provision.
-Cliff
Cliff's Note: The third day was the first day of life, just as the third day was our first day of salvation.