(CBS NEWS) – New artifacts have been found on the legendary Spanish galleon San Jose, Colombia’s government announced Thursday, after the first robotic exploration of the three-century-old shipwreck. Dubbed the “holy grail” of shipwrecks, the San Jose was owned by the Spanish crown when it was sunk by the British navy near Cartagena in 1708. Only a handful of its 600-strong crew survived.

In February, the Colombian government announced it would begin extractions from the ship off its Caribbean coast, with the wreckage believed to be holding treasures worth billions of dollars. “Results of this exploration have revealed an unprecedented set of archaeological evidence, which has greatly expanded our knowledge,” the institutions in charge of exploring the wreck said in a statement.

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It said a robot surveyed the wreck, whose exact location has been kept secret since its discovery in 2015, between May 23 and June 1, covering an area “equivalent to more than 40 professional soccer fields.”