Apparently Europeans don’t get sarcasm.
You don’t need a wall. You don’t even need a wall in the States, if the border patrol would be allowed to do its job properly.
Looks like 10 miles would be more than enough.
The problem is that Spain has already done that, and the “migrants” rush the wall and overwhelm the Guardia Civil and any other forces there. The new government - which is not just old style Socialist, but radical leftist - has invited more ¨migrants,¨ almost all of them Muslims, and Spaniards are very upset. But the left and the leftist press rule in Spain, so lots of luck if you’re just an ordinary little Spaniard.
Shooting at sight would be the cheapest option.
Sinking the invasion boats.
Spain is not unfamiliar with the modern use of walls. They are very familiar with the Moroccan Western Sahara Wall
https://en.wikipedia.org/wiki/Moroccan_Western_Sahara_Wall
You could try sending out your ships to intercept their boats, seize all the money from the captain, sink the boat, and take them back.
Dw article: In the Morocco mountains, thousands of African refugees lie in wait for their chance to cross the border fence into Ceuta. The Spanish enclave has become an increasingly popular destination for migrants headed to Europe.
The Spanish guy knows this, but prefers to make fun of Trump, knowing that the left is too lazy to check a map.