Hidden Passage Beneath the X-Marked Library Tile

A concealed vertical shaft beneath the Venetian library's floor, accessed by smashing an X-marked tile. The two-foot-square opening emits cold, rancid air from ancient depths, serving as the entrance to the Grail's tomb. Elsa descends first, followed by Indiana Jones and Brody, transitioning from the library's scholarly atmosphere to the shadowed perils of the subterranean tomb. The passage bridges the library's hushed aisles to the damp, foreboding stone of the Crusader-era tomb below, where Nazi threats loom as the group begins their perilous descent.