Now these are the generations of the sons of Noah,
Shem, Ham, and Japheth:
and unto them were sons born after the flood.
Genesis 10:1
"Conditions for travel by both people and animals were affected by the
Ice Age, which occurred after the Flood as the result of two
unrepeatable conditions.
- The oceans contained warm water because of widespread exposure to
magma, volcanic eruptions, and recently released hot subterranean water. The warm waters easily evaporated and formed clouds, producing massive amounts of snow during the winter months and frequent rains during the summer months.
- The summer months were often cooler than usual because large amounts of volcanic ash in the air from widespread volcanic eruptions blocked the sun’s rays. The cooler temperatures of summer only allowed a partial melting of each year’s winter snows, so ice packs began to build up on the land. The persistence of warm oceans and cool summer temperatures resulted in more and more ice accumulations outside the temperate regions.
--The accumulation of ice eventually became so massive that sea levels
became lower.
--This exposed more and more of the continental shelf as dry
land. Numerous islands, peninsulas, and land bridges became visible
above the ocean levels. The Siberian land bridge allowed many animals
and people to walk across dry land from northern Asia to North America.
There were likely many other land bridges to places such as Australia
and the British Islands. 
It’s easy to see from the pyramid belt and other remains of cities that
the first civilizations were in the temperate regions of the earth. At
this time, there would have been many well-watered places with rich
soils in which to establish their communities.
Hunters and explorers are
bound to have explored the frozen regions
of the earth, but these
inhospitable areas were not suitable places for building large cities.
During the Ice Age, people began to build cities, temples, and other
structures near the seashores. Then eventually, the conditions causing
the Ice Age began to reverse. Ocean temperatures cooled, ice sheets
melted, and ocean levels rose. The manmade structures that existed near
the sea were gradually covered with water, and many islands disappeared
beneath the ocean.
Architectural remains of stairs, level rock foundations, sculptures,
columns, and other manmade structures are found around the earth on the
continental shelves and in shallow seas. Archeologists often attribute
their underwater positions to earthquakes or tectonic plate movements.
*However, an even more logical explanation is that when the Ice Age was
ending, the ocean levels began to gradually rise."
CC