Adolf Guyer-Zeller First thought of the idea of a tunnel in 1893, and at that point, he had planned to have 7 stations inside the tunnel before reaching the peak of the Sphinx.
Adolf Guyer-Zeller fik ideen til en tunnel i 1893 og planlagde på det tidspunkt at bygge syv stationer inden i tunnelen, før man nåede, hvad der nu er Sphinxen.