Here, migrants are prevented from entering the European Union, with journeys becoming increasingly dangerous

Quetta is a Spanish enclave in North Africa next to the Strait of Gibraltar and has a land border with Morocco – there's also a six-metre-high wall that runs less than a mile.

It was once a place where migrants tried to cross into the European Union, but today it stands desolate and empty.

In one day, Morocco sent more than 15,000 people to Quetta. But when Spain changed its policy, immigration stopped almost completely, says Jesús Verdo Baeza, a political scientist at the University of Cádiz in Andalusia.

Spain's agreement with Morocco criticized: “A danger to Europe”

In short, the informal agreement between Spain and Morocco stipulates that all migrants in Ceuta and Melilla be stopped in exchange for Spain's investment in Morocco.

Spain should also refrain from criticizing the country's policy in Western Sahara – something that has drawn criticism.

– It is dangerous for Europe. “It is not completely safe to allow dictators to control our borders,” says Jesús Verdo Baeza.

The flow of migrants has stopped – and they are now taking dangerous routes

The agreement caused the flow of migrants across the Mediterranean to Spain to stop almost completely. Now instead completely different paths are being taken which could be much more dangerous.

There are much longer routes, which greatly increases the risk of dying at sea or somewhere along the way, says Ilarji Mayor, who works to identify people who die during the journey.

Watch the clip: This is the wall between Spain and Morocco to prevent migrants from reaching the European Union.