The Basilica di San Marco holds 8,000 square metres of gold-ground mosaics—more than any other church in Christendom. Commissioned across eight centuries, from the eleventh through the nineteenth, these tesserae chronicle Biblical narrative and Venetian ambition in equal measure. The Pentecost dome alone required 24 kilograms of gold leaf, applied in thin sheets over glass cubes that catch and fracture candlelight into a shifting, honeyed glow. Venice constructed the basilica in 1063 to house the relics of Saint Mark, smuggled from Alexandria two centuries earlier beneath layers of pork fat to evade Muslim customs inspectors. The building's floor plan mirrors Constantinople's Church of the Holy Apostles—five domes arranged in a Greek cross, each supported by pendentives that distribute 500 tons of stone and brick across marble columns looted from Byzantine temples. The Pala d'Oro, a jeweled altarpiece commissioned in 976 and expanded through 1345, contains 1,300 pearls, 400 garnets, 300 sapphires, and 90 amethysts set in gilt silver panels that recount the life of Christ and the martyrdom of Mark. Today the basilica receives 20,000 visitors daily during summer months, compressing sightlines and shortening dwell time in the atrium. Evening access, when permitted through guided programs, reduces ambient noise and allows longer study of the Creation mosaics in the narthex—six domes depicting Genesis in 24 concentric bands, each scene labeled in Latin majuscule. The Treasury, housed in a vaulted room south of the sanctuary, displays 283 objects seized during the 1204 Sack of Constantinople, including Islamic rock crystal ewers and Byzantine chalices that predate the basilica itself. St Mark's Basilica tours at night prioritize the upper galleries and choir chapels, spaces closed during standard daytime entry. The Museo di San Marco, accessible via steep stairs behind the facade, holds the original Horses of Saint Mark—four bronze stallions cast in the fourth century, transported from the Hippodrome of Constantinople, and displayed on the western loggia until atmospheric pollution forced their removal in 1982. The replicas visible from Piazza San Marco weigh 900 kilograms each; the originals, now climate-controlled, retain traces of Roman gilding beneath medieval repairs.