Mount Hua in China (or Hua Shan) has two walking trails to the various summits (with associated temples). Legend has it that reaching each temple and tea house grants one immortality.
The traditional trail, which reaches 5 of the mounts peaks, was first developed in the third or fourth centuries AD. The track has been made safer by the authorities (by closing sections off) but is still quite hair-raising in parts.
Also make sure you look at El Caminito Del Rey in Spain.
Otherwise, have a look at these topics?