It spread Anglo-European culture across the nation and caused trade to flourish, but the story of the Chinese labourers who built the track has largely been forgotten.
Did Vikings find their way to a remote part of Oklahoma? Some in a small community believe so, thanks to controversial runic carvings found in the area.
A drive down Bolivia's infamous "Death Road" takes travellers into a world where two resources have provoked fascination, misunderstanding and controversy for centuries: coca and gold.
Showcasing eight towns and villages, the stunning road brings a different kind of sunshine to the French Riviera, when the region breaks out in giant brushstrokes of rich yellow.