If you believe the Bible this passage of Scripture below will mean a lot to you in that it helps us in our understanding of the world after the worldwide flood. Sadly, those who do not believe come up with so ever many different theories.
Genesis 8:13 “¶ And it came to pass in the six hundredth and first year, in the first month, the first day of the month, the waters were dried up from off the earth: and Noah removed the covering of the ark, and looked, and, behold, the face of the ground was dry. 14 And in the second month, on the seven and twentieth day of the month, was the earth dried.15 ¶ And God spake unto Noah, saying, 16 Go forth of the ark, thou, and thy wife, and thy sons, and thy sons’ wives with thee. 17 Bring forth with thee every living thing that is with thee, of all flesh, both of fowl, and of cattle, and of every creeping thing that creepeth upon the earth; that they may breed abundantly in the earth, and be fruitful, and multiply upon the earth. 18 And Noah went forth, and his sons, and his wife, and his sons’ wives with him”

Pic 1. Note the bed of sea shells roughly 100 m (300 feet) above sea level in back ground. Location west coast New Zealand north Island, south west of Hamilton.
Pic 2. Island off west coast of Scotland showing flattened surface from previous sea level wave action. Bump is former size of the island before sea level dropped.
Pic 3. Island sea stack formation near Oban Scotland. Castle in the background would have had much greater security when it was surrounded by water.
Pic 4. Note dark band along top of cliff on south coast Victoria Australia. See close up next pic.