For centuries, historians have believed that Cleopatra VII was buried alongside her lover, Mark Antony, in Alexandria—but their tomb has never been located. Now, scientists may be closing in on a major clue.

Archaeologist Kathleen Martínez, working alongside renowned oceanographer Bob Ballard and a team of underwater researchers, has reportedly identified what could be a sunken port in the Mediterranean Sea near the ruins of Egypt’s Taposiris Magna temple, according to National Geographic.

The submerged structure lies near a 4,265-foot underground tunnel that historically connected the temple to the sea, a feature that may have played a role in burial practices or ceremonial access during Cleopatra’s time.

A series of large underwater buildings—“arranged in rows and over 20 feet high”—was also uncovered. The structures included polished floors, cemented blocks, columns, smooth stone, and multiple anchors, along with storage jars that date to Cleopatra’s era, according to National Geographic.

These findings suggest that the site could have once functioned as a port used by the famed Egyptian queen. Martínez’s theory posits that Cleopatra’s body may have been brought to Taposiris Magna before being interred in the temple, hidden from Roman eyes. In this scenario, her remains would have been transported via the port and moved through the 4,265-foot underground tunnel to their final resting place.

While many historians maintain that Cleopatra and Mark Antony were buried together in Alexandria, their tomb has never been located. Martínez, however, theorizes that Cleopatra may have devised a secret plan to protect their burial from the Romans.