Hundreds of thousands of migrants attempt to travel from Africa to Europe every year in search of economic opportunities or to escape conflict and violence. Many take perilous routes across the Sahara and Mediterranean, where the risks can be deadly.

The true death toll is unknown, as many incidents go unreported. But migration experts say the routes are among the world's most dangerous, exposing migrants to harsh conditions, violence and exploitation.

The trans-Saharan routes include three major corridors. The Western Atlantic corridor runs from West Africa through Mauritania to Western Sahara and southern Morocco. 

Another follows the Mali-Algeria-Morocco axis, while a third runs from Niger through Algeria and connects to Libya.

"What people face is a wide range of incidents from extortion at checkpoints, arbitrary detention, kidnapping, physical violence, sexual violence, forced labor, risk of arrest, sometimes dumped in the desert further south again when intercepted by authorities," said Bram Frouws, director of the Migration Center in The Hague.

The International Organization for Migration's Missing Migrants Project has recorded more than 2,000 deaths along the Sahara since 2014. Experts say the actual number is likely to be significantly higher because many deaths are never reported or documented.

For those who survive the desert crossing, the journey can become even more dangerous as they attempt to cross the Mediterranean into Europe. Some migrants turn to smugglers, while others try to organize crossings themselves because they cannot afford the fees charged by smugglers.

"The different trajectories of migration don't all include smuggling. It only happens at the very last bit when people want to cross into Europe and only by those that can afford it," said Miriyam Aouragh, a professor of digital anthropology in Morocco. 

"Most people can't, and that's why for most people it is very dangerous. They organize their own small boats."

Others try to reach the Spanish enclave of Ceuta by crossing a heavily fortified border with Morocco. Earlier this month, border controls were overwhelmed as tens of thousands of migrants attempted to cross, prompting Spain to deploy additional police and military personnel.

European efforts to curb migration have also changed the economics of the journey. Frouws said increased efforts to restrict migration were driving up demand for smugglers and the prices they charge. 

"Because of the increased efforts by Europe to reduce or stop migration, their profits are increasing, the demand for their services is increasing, the prices they can charge for their smuggling services are increasing. So for them it is actually a good thing. They are the big winners," he said.

Migration experts say expanding legal pathways and regulated labor migration could provide safer alternatives for people seeking opportunities in Europe, while reducing their reliance on dangerous routes and criminal smuggling networks.