At Choum, at kilometer 460 of the 652 km long railroad line, the railroad makes a 90 degree turn, even before the mountain massif visible in the background, and then heads north to Zouérate instead of east. This is due to the border between Mauritania and the territory of Western Sahara. Since 1991, the railroad line has run for around 5 kilometers across the territory of Western Sahara (as does the paved road running next to it); previously, it ran through a 2-kilometer tunnel in the mountain massif to bypass the territory of Western Sahara.
