Matt Rendell explains the crucial role of the cartographers in mapping out every Tour de France stage: for Peter Sagan's win in Seraing, an entire roundabout had to be removed.

"Race maps, alternative routes, gradients, profiles, hotel locations, parking plans ... without hundreds of different maps, it just couldn't take place," explains Matt.

For Sagan's win in Boulogne-sur-Mer, access roads had to be opened up to let in the HGVs, while pavements were taken up in Metz to widen the final straight.

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