What 4 places used to be covered in water?

Several places that were once covered in water include the Sahara Desert, which was a vast inland sea millions of years ago, and the Great Plains of North America, which were submerged under the Western Interior Seaway during the Late Cretaceous period. Additionally, the current location of the Mediterranean Sea was once a dry landmass before the Zanclean Flood. Lastly, the area now known as the English Channel was also dry land during the last Ice Age, connecting Britain to mainland Europe.