Saint Mark's Basilica is one of the most audacious acts of architectural theft in history. Built in 832 to house the bones of St Mark, smuggled out of Alexandria beneath a layer of pork to deter Muslim inspection, it has never stopped accumulating other people's treasures.

The four bronze horses above the main portal were looted from Constantinople in 1204. Napoleon then looted them again, carting them to Paris before they were returned in 1815 to general jubilation. The horses on the facade today are copies. The originals live inside, too fragile now for seagulls and weather.

The facade glitters with 86,000 square feet of golden mosaics and fragments plundered from ancient sites across the Mediterranean. It was always as much a statement of power as a place of prayer.

VoiceMap's audio tours trace the basilica's role as Venice's political and spiritual centrepiece, connecting its mosaics, looted sculptures and bronze horses to the rivalries, crusades and Napoleonic upheavals that shaped the city.