The Boston Public Library is a municipal public library system founded in 1848 in Boston, Massachusetts, holding approximately 24 million items and ranking as the third-largest public library in the United States behind the Library of Congress and the New York Public Library. Its Central Library in Copley Square — a Boston Landmark since 2000 — houses an extensive rare maps and archives collection that draws researchers from around the world. Among those holdings are historical documents from the colonial and early American eras, including cartographic records that have proved directly relevant to maritime archaeology. Gates visits the library in Season 14 of Expedition Unknown to examine an early 18th-century map drawn by Captain Cyprian Southack, a document that would prove pivotal to the decades-long search for the pirate ship Whydah Gally, which sank off Cape Cod in 1717 with what Gates describes as "the largest stolen fortune in the golden age of piracy."
The Whydah Gally sinks off Cape Cod; Captain Cyprian Southack is dispatched to the area and later produces a map marking the approximate location of the wreck.
The Boston Public Library is founded, eventually becoming one of the largest public library systems in the United States.
Treasure hunter Barry Clifford rediscovers Southack's map — reportedly housed in the BPL archives — and uses it to help locate the Whydah wreck site.
The BPL's Central Library in Copley Square is designated a Boston Landmark by the Boston Landmarks Commission.
Gates visits the Boston Public Library archives in Expedition Unknown S14E05 "Dive for America's Pirate Loot" to examine Southack's historical chart.
The Whydah Gally is among the most historically significant pirate wrecks ever found in North American waters. Captain Samuel "Black Sam" Bellamy's ship sank during a nor'easter in April 1717, and according to the episode, the disaster took more than 180 lives. Captain Cyprian Southack — a skilled colonial-era cartographer — was sent to the scene almost immediately, and the chart he produced is considered one of the earliest firsthand records of the wreck's location. That map's survival in a major archive like the Boston Public Library illustrates how documentary history and underwater archaeology can reinforce each other across centuries.
Barry Clifford, whose team is credited with locating and excavating the Whydah wreck site beginning in the mid-1980s, has long pointed to Southack's map as a foundational piece of evidence in that search. The wreck is notable not only for the treasure reportedly aboard — the episode cites more than £20,000 in gold and silver at the time of sinking — but also for the historical record it provides about the golden age of piracy. Artifacts recovered from the site have been studied by maritime archaeologists and are displayed at the Whydah Pirate Museum in Yarmouth, Massachusetts.
The Boston Public Library's role in this story is a reminder that archives can be as consequential to exploration as any shovel or dive tank. The BPL's rare maps and manuscripts collections are maintained for public and scholarly access, and the library's status as Massachusetts' Library for the Commonwealth means its resources are available to all adult residents of the state — a democratic principle that, in this case, extends to pirate hunters.
Gates' visit to the BPL in S14E05 frames the archive stop as the historical grounding for the episode's underwater fieldwork off Cape Cod. The episode does not claim new archival discoveries at the library itself; rather, the BPL segment contextualizes why Clifford's team knew where to look — and sets up the dive sequences that follow. Whether the full extent of Bellamy's fortune has ever been recovered remains an open question that the episode explores without resolving definitively.
The Boston Public Library was founded in 1848, making it one of the oldest large municipal public libraries in the United States.
The BPL holds approximately 24 million items, ranking it third-largest among public libraries in the country, behind only the Library of Congress and the New York Public Library.
All adult residents of Massachusetts are entitled to borrowing and research privileges at the BPL, as it serves as the state's Library for the Commonwealth.
The Central Library in Copley Square was designated a Boston Landmark by the Boston Landmarks Commission in 2000.
The Boston Public Library's Central Library on Copley Square is generally open to the public and free to enter, with the research and special collections departments accessible to those seeking archival materials. Visitors can explore the landmark McKim building's renowned architecture, murals, and courtyard in addition to its collections. Check the BPL's official website for current hours and any access requirements for special collections, as research appointments may be required.
Boston, Massachusetts — the library is located in the city's Back Bay neighborhood, directly on Copley Square.
The library is open year-round, though spring and fall tend to offer more comfortable weather for exploring Boston's Copley Square neighborhood. Summer brings heavier tourist traffic to the area.
Whydah Pirate Museum, Yarmouth
The Whydah Pirate Museum in Yarmouth, Massachusetts, houses artifacts recovered from the same Whydah Gally wreck that the BPL's Southack map helped locate — both sites are directly connected to the S14E05 Expedition Unknown investigation.
Mercer Museum, Doylestown, Pennsylvania
The Mercer Museum in Doylestown represents another instance of Gates consulting an institutional archive or collection to track down historical treasure leads, echoing the BPL's role in the Whydah investigation.
Historical data sourced from Wikipedia