Choum

Mauritania Railway route.

The town stands on a spur of land which carries the major turning-point in the border between Mauritania and the Western Sahara. In the early 1960s, the French colonial authorities in Mauritania wished to build the line from Nouadhibou to Zouérat to exploit the iron ore reserves at Zouérat. The Spanish authorities then responsible for the Western Sahara negotiated to allow the railway to be built through Spanish territory over relatively level desert, but imposed conditions unacceptable to the French. The French engineers therefore built the line parallel with the border and tunneled through the Choum hill spur — two kilometres through solid granite just to stay within French territory. The tunnel has been called a "monument to European stupidity in Africa".[2] The absurdity was highlighted when the southern part of the territory of Western Sahara was briefly administered by Mauritania after the Spanish withdrew in 1975/1976. The tunnel is no longer in use and a 5 km section of the railway cuts right through the POLISARIO controlled part of the Western Sahara (21.354867°N 13.012644°W / 21.354867; -13.012644).

The N1 highway from Atar now runs all the way to north Zouérat, but the sandy track paralleling the railway west to Nouadhibou traverses low dune cordons so is much easier in a 4WD. Regular vehicles can be loaded onto a flatbed wagon at Choum.