Choum Tunnel in Choum, Mauritania

When the Mauritanian iron ore railway was being constructed in the 1960s, this line of track through the desert had a problem.

Officials within the region, at this point still under the auspices of French colonialism, indentified that the most convenient route for the train would in fact briefly go through Western Sahara, at this point territory controlled by Spain.

Rather than the involvement of diplomacy, and likely monies given to the Spanish government, it was instead decided to tunnel through two kilometres of granite in the mountainside near the town of Choum.

Initially, the iron ore train did run through this tunnel. However, in 1991, it was decided by railway bosses within the now independent Mauritania that it was actually more convenient to run a small part of the track through the now contested territory of Western Sahara after all.

The tunnel now lies abandoned a few kilometres from the revised track, a silent monument to colonial obstinacy of decades past.

The tunnel is still open to drive or even walk through, though once you are few metres into it you can expect to be in near total darkness until coming out on the other side.