A National Geographic Explorer’s search for Cleopatra’s tomb got a big breakthrough.

Kathleen Martínez has dedicated two decades to the quest for Cleopatra’s lost tomb. Her efforts are part of a new National Geographic program titled “Cleopatra’s Final Secret.”

According to Martínez, Cleopatra, disliked by the Romans, might have arranged for her body to be clandestinely transported to the Taposiris Magna temple in Egypt via underwater tunnels for burial.

Her recent expedition led her team underwater, where they uncovered an ancient submerged port located several miles from Taposiris Magna in the Mediterranean Sea.

In an exciting moment captured in the video above, Martínez called renowned National Geographic Explorer Bob Ballard, who famously discovered the Titanic, to report her findings.

“I’m grinning from ear to ear,” Ballard replied. “We believe there’s an island with a port connected by a tunnel that leads from the temple to that very area. It doesn’t get any more thrilling than this.”

“After 2,000 years nobody has ever been there,” Martínez told her team. “We are the first ones.”

You can read more about the fascinating discovery on nationalgeographic.com.

“Cleopatra’s Final Secret” premieres Sept. 25 on National Geographic and streams the next day on Disney+ and Hulu.

The Walt Disney Company is the parent company of National Geographic and this ABC station.