We waded across a swollen, icy river and clambered up a steep mountainside, the exhilaration of the adventure easing our apprehension.

There's no route as such, just a nerve-jangling jungle scrabble up a shockingly steep mountainside, over a surface that's alternately slimy mulch and bare rock.

Today guides show you around the colourful streets that stagger up the steep mountainside, where access has been improved by escalators, the longest outdoor moving staircases in the world.

Instead, it deposits them directly on a steep mountainside.

To the east, a steep mountainside provides a natural defence while on the other sides, a wide, deep moat cut into the rock isolates and protects the site.