Thirteen kilometres along the most expensive stretch of railway the Russian Empire ever built.

The Circum-Baikal line was carved into the cliffs above the world's deepest lake between 1899 and 1905 — forty tunnels, dozens of bridges and stone galleries.

What you get instead of climbing is texture. The profile ripples constantly — a 6% kick at km 10, a sharp 9% drop at km 7, dozens of smaller ones — as the gravel track meanders beside the gentler railroad bed.

A fast, rolling ride along a cliff ledge in southern Siberia, with 1,600 metres of lake water directly below you.