I've both ridden and driven #1 - Col de Turini.... and same applies to the much more boring #18 - Spaghetti Junction.... but the most memorable of em was #15 - Los Caracoles, (
"the road requires extreme patience and skill to negotiate" << do I get a discount on my insurance now?
) ascending from the coastal plains of Santiago to the Argentine side of the high Andes. Sadly done in an Argentine-bulit Fiat Duna (an aptly named vehicle if ever there was one) rather than on 2 wheels...