Tucked away from the tourist crowds of St. Mark's Square and reachable only through Venice's labyrinth of canals, the Cloister of St. Apollonia is believed to be among the oldest surviving Byzantine cloisters in the city. Most visitors to Venice never find it — which is part of what makes it such an intriguing repository for one of the Adriatic's more quietly kept secrets. The cloister is used by the church to store significant architectural and archaeological fragments, including a carved limestone block that was reportedly discovered embedded in the wall of St. Mark's Basilica's crypt during archaeological work believed to date to the 1960s. That block — featuring imagery that some researchers have associated with Macedonian funerary traditions — is the reason Josh Gates made the trip here for Expedition Unknown. Gates came not to see the tourist Venice, but to examine a relic that, according to at least one researcher, may once have adorned the sarcophagus of Alexander the Great himself.
The Cloister of St. Apollonia is believed to have been constructed, and is considered among the oldest Byzantine-style cloisters in Venice — though precise dating should be treated as approximate in the absence of confirmed scholarly sources.
Archaeological work in the crypt of St. Mark's Basilica reportedly uncovers a carved limestone casing block embedded in the crypt wall; the block is subsequently stored at the Cloister of St. Apollonia.
Josh Gates investigates the limestone block at the Cloister of St. Apollonia alongside imaging expert Pietro Meloni in Expedition Unknown S13E02, "Alexander's Lost Tomb."
Imaging expert Pietro Meloni, who appears on camera with Gates at the cloister, guided the physical examination and 3D documentation of the limestone block. Meloni's role was technical rather than interpretive — he operated the Artec Leo scanner that produced the ultra-detailed digital model of the block's carved surfaces. The interpretive leap — that the block may have once adorned Alexander the Great's sarcophagus — is attributed in the episode to "one researcher," though that researcher is not named on camera at this location.
The carvings on the block include what Gates and Meloni identify as a Vergina Star (the sunburst symbol associated with the ancient Macedonian royal house) and what appears to be a sarissa, the long-handled spear pioneered by Philip II of Macedon and famously deployed by Alexander's armies. Both symbols appear in documented Macedonian funerary contexts, which is the basis for the hypothesis the episode explores. The block was reportedly found during archaeological work in St. Mark's crypt in the 1960s, a period of significant excavation activity in the basilica — though the precise circumstances of its discovery and any formal scholarly publication about it are not confirmed in the available evidence.
The broader theory the episode investigates — that Alexander's remains may have been brought to Alexandria, then transferred to Venice alongside (or instead of) the relics of St. Mark in the 9th century — is a hypothesis associated with a small number of independent researchers. Mainstream Egyptology and classical scholarship generally hold that Alexander was buried in Alexandria and that his tomb's current location is unknown, likely lost to ancient city development. The identification of any artifact as definitively connected to Alexander the Great requires a standard of archaeological evidence that has not yet been publicly met by this block.
What Gates' episode contributed is a high-resolution 3D scan of the limestone block, intended to allow comparative analysis against the sarcophagus held at the British Museum. Whether that comparison yielded a match is explored later in the episode, but the cloister segment itself ends without a definitive conclusion — Gates frames it as gathering data, not solving the mystery. The episode is careful to present the block as suggestive rather than proven, which is the honest position given what is currently known.
The Artec Leo scanner used by Pietro Meloni to document the limestone block captures approximately 40 photographs per second and produces models accurate to within fractions of a millimeter — the same class of technology used in heritage preservation of fragile artifacts.
The Vergina Star, carved on the block, is a sunburst symbol found on artifacts associated with the ancient Macedonian royal house, including the famous gold larnax discovered in the royal tombs at Vergina, Greece.
The sarissa — the long-handled spear Gates identifies on the block — was reportedly between 15 and 21 feet long and was considered a decisive tactical advantage that helped Alexander's armies defeat far larger forces across Persia and beyond.
The Cloister of St. Apollonia is believed to be among the oldest Byzantine-style cloisters surviving in Venice, making it historically significant quite apart from any Alexander-related mystery.
The Cloister of St. Apollonia is generally considered one of Venice's lesser-known sites, located near St. Mark's Basilica but well off the main tourist circuit. Access policies and opening hours may vary depending on whether the space is in active church or museum use, so visitors are strongly advised to check current local information before planning a trip. The cloister is not a standard public museum, and the limestone block examined by Gates is a stored ecclesiastical artifact rather than a display piece — public access to it specifically cannot be assumed.
Venice, Italy — the cloister is located within the city itself, in the Castello sestiere near St. Mark's Square.
Venice's shoulder seasons — spring (April–May) and early autumn (September–October) — generally offer more manageable crowds and pleasant weather for exploring the city's quieter corners. Summer brings significant tourist congestion throughout the city, which can make navigating the canal-side lanes around lesser-known sites more difficult.
St. Mark's Cathedral
St. Mark's Basilica is where the limestone block was reportedly discovered in the crypt during 1960s archaeological work, making it the direct origin point of the artifact Gates examines at the cloister — both sites are central to the same S13E02 investigation.
Church of San Nicolò al Lido, Venice
The Church of San Nicolò al Lido is another Venetian ecclesiastical site investigated during the same Alexander the Great episode, exploring the story of how St. Mark's relics arrived in Venice from Alexandria.
Alexandria
Alexandria, Egypt, is the city where Alexander the Great was buried according to ancient sources and where his tomb is believed by most mainstream scholars to still lie lost — making it the ultimate destination of the mystery Gates traces through Venice.