The thickness of the walls should be sufficient for two armed men to pass each other with ease.
Marcus Vitruvius PollioArchitects should be educated, skillful with the pencil, instructed in geometry, know much history, have followed the philosophers with attention, understand music, have some knowledge of medicine, know the opinions of the jurists, and be acquainted with astronomy and the theory of the heavens
Marcus Vitruvius PollioOak... lasts for an unlimited period when buried in underground structures... when exposed to moisture... it cannot take in liquid on account of its compactness, but, withdrawing from the moisture, it resists it and warps, thus making cracks.
Marcus Vitruvius Pollio