Wren's masterpiece features a double-shelled dome standing 111 meters tall. The inner brick cone supports a gilded lantern, while the outer lead dome acts as an acoustic hemisphere. The Whispering Gallery creates acoustic sound reflection, carrying whispers across a 33-meter diameter circle.
The full decipherment and its observational protocol — where to stand, when, and what to watch for — are in the London field codex.
Or read the complete Florence codex free first.