horogeneesi

https://youtu.be/Z0QaampHKkE?feature=shared

https://youtu.be/bVn04eJRjV4?feature=shared

Mannerlaatat (Plate tectonics explained)

https://youtu.be/kwfNGatxUJI?feature=shared

https://youtu.be/uBCHVdYmjr0?feature=shared