Strangemaps provides a map of the lizard people tunnels underneath Los Angeles, as discovered by mining engineer G. Warren Shufelt in the 1930s using his radio X-ray, i.e. pendulum. Pics and text from the contemporary LA Times article.

So firmly does Shufelt and a little staff of assistants believe that a maze of catacombs and priceless golden tablets are to be found beneath downtown Los Angeles that the engineer and his aides have already driven a shaft 250 feet into the ground, the mouth of the shaft being on the old Banning property on North Hill street overlooking Sunset Boulevard, Spring street and North Broadway.

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According to the legend as imparted to Shufelt by Macklin, the radio X-ray has revealed the location of one of three lost cities on the Pacific Coast, the local one having been dug by the Lizzard People after the “great catastrophe” which occurred about 5000 years ago. This legendary catastrophe was in the form of a huge tongue of fire which “came out of the Southwest, destroying all life in its path,” the path being “several hundred miles wide.” The city underground was dug as a means of escaping future fires.