“A Disc of light moves across the cathedral floor. The marble in its path lights up, revealing deeply colored swirls, rich with hues of burgundy, plum, caramel, and ochre. It is ancient rock, stained by terrestrial chemistry and by the infernal pressures of the inner Earth. Its surface is smooth and nearly reflective, testament to extraordinary craftsmanship but also to the effects of hundreds of years’ worth of penitent feet processing through the looming shadows of the church interior. The air smells of smoke and candle wax, and the occasional perfume of a passing tourist.
The source of this light is a hole punched through the roof of the church high above, elaborately accentuated by a brilliant halo of golden rays, painted to resemble the sun. The hole acts like a film projector. Daylight streams through, creating a narrow beam of illumination visible only in the presence of smoke or dust, as if something otherworldly has been forced into material form….”
Read more at the Source: Why Catholics Built Secret Astronomical Features Into Churches to Help Save Souls | Atlas Obscura