Silk Road Ghosts takes the viewer off the beaten path as I ply a circuit, following in the footsteps of the ancient conquerors, passing through some of the more remarkable parts of Central Asia's Silk Road. From Almaty in Kazakhstan, I set out towards a daunting rendezvous with the Darvasa Gas Crater in Turkmenistan. Along the way I dot many of the road's pivotal locations, bearing witness to its myriad ghosts which served to glorify the annals of our planet's history.

• Stephen French