The Czech Republic and Slovakia, which once was Czechoslovakia.
Well , fossils were found ! : D
No countries dominated Western Europe after WW2 as all Nazi-occupied countries were freed and become independent once more.
North America and Europe were once joined together as part of the supercontinent Pangaea. Over millions of years, these landmasses drifted apart due to plate tectonics, forming the Atlantic Ocean between them.
It was a part of the continent of North America, Greenland has now been associated with Europe.
Up to 1993, Slovakia and the Czech Republic were a single country called Czechoslovakia. They are now two independent countries.
North America and Europe had matching rocks and minerals found, indicating that these continents were once joined together as part of the supercontinent Pangaea.
Laurasia was the northern landmass that broke away from Pangaea. The modern day continents located in Laurasia were Europe (without Balkans), Asia (without India), and North America. Gondwana was the southern landmass that broke away from Pangaea. The modern day continents and countries located in Gondwana were Africa, South America, Australia, India, Arabia, Antarctica, and the European Balkans.
South america and Africa were once joined.
It was once attached to North America.
They were not invited. Countries are not invited to join. Countries must apply to join. So it was the Czech Republic's decision to apply and once their application was approved, they were able to join. They joined in May 2004.
Britain has been an island, or group of islands for many centuries. Once joined by land to continental europe, but this was in pre history. At the end of the last glaciation people could walk from Europe to Britain, but as sea level rose because of the melting ice, the southern North Sea flooded and broke through the narrow piece of land joining Britain to the mainland of Europe near what is now Dover.
Once you are inside the EU (Schengen) you do not need visa to travel within the 27 countries.