Khao Luang Caves, Phetchaburi (Phetburi), Thailand is a complex of three caves housing numerous Buddha images and pagodas, many put in place by King Rama IV. Rama IV often used the caves for meditation prior to ascending the throne. The caves lie just outside the town of Phetchaburi which is approximately two hours south of the capital, Bangkok.
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Subversia, Hidden Underground City of the Dragonmen [fiction: "The Dragon's Back" Christian Fantasy Trilogy]