This is a quote about the 727 from the Boeing website:
"First jetliner to prove it could operate -- even with one engine out -- from Bogata, Colombia (8,355-foot elevation), Cuzco, Peru (10,800-foot elevation), and LaPaz, Bolivia (13,358-foot elevation). No jet had operated at any of these airports before."
Where in South America is "El Alto" airport? I've heard that name before as being one of the highest but I forgot where it is. I heard that after some prop planes takeoff, they're actually cleared to a LOWER cruising altitude!