Where does Africa join Europe? What is the evidence?

between Europe and Asia (dividing Eurasia) : along the Turkish Straits, the Caucasus and the Urals (historically also north of the Caucasus, along the Kuma-Manych Depression or along the Don River) between Asia and Africa (dividing Afro-Eurasia into Africa and Eurasia) : at the Isthmus of Suez.

Though Europe and Africa do not share any physical borders on the ground, the African plate meets the Eurasian plate in the middle of the Mediterranean sea.

Explanation:

The lighter African plate from the side of its extreme north has apparently subducted below the heavier Eurasian plate right in the middle of the Mediterranean Sea. This subduction is believed to be so deep that the subduction boundary can no more be seen.