Cathedral Edge: HH 901 Carves Mystic Mountain I positioned the observer 2.5 light-years inside the Carina Nebula, eye-level with the southern pillar’s sunward face as the 0.8 light-year-wide trunk rises three light-years out of frame. Here we witness HH 901 (35,000 K, ~250,000 L☉) blasting a 10,000 K H-alpha/OIII bow of photoevaporating gas from a 12 K molecular wall, its ultraviolet chiseling a razor [S II]/[O III] shock along the right margin and casting cathedral-long shadows across a glowing dust screen. This frame captures the exact moment infant starlight both reveals and transforms its parent cloud—teal rims, electric pink fronts, and amber embers held in sacred hush—an impossible, close vantage no telescope could survive, yet rendered with telescope-grade fidelity.