Since I’ve seen the video of those two tracks I cannot take them off my head. They are defined as the most dangerous in the world, and looking at the images, it looks promising.
1. Mount Huashan – China
Here some videos:
More about it (with photos as well), here.
2. Caminito del Rey – Spain
I’m not sure it is open, I haven’t checked yet.
Here some videos:
Short version
They are amazing! 🙂