Archaeologists have discovered an intact, ancient Egyptian tomb in the Valley of the Kings, the first since King Tutankhamun's was found in 1922.
A University of Memphis-led team found the previously unknown tomb complete with sarcophagi and five mummies.
The archaeologists have not yet been able to identify them.
But Egypt's chief archaeologist Zahi Hawass says they "might be royals or nobles" moved from "original graves to protect them from grave robbers".
"We don't really know what kind of people are inside but I do believe they look royal. Maybe they are kings or queens or nobles," he told Reuters news agency.
Bob Partridge, of Ancient Egypt magazine, said it could possibly be the tomb of Queen Nefertiti, who co-ruled Egypt between 1379 and 1358 BC. Her tomb has never been found.
"Nefertiti was probably buried to the north of Egypt at a place called Akhetaten," he told BBC News24.
"It's believed that the burials there, which included Nefertiti and some of her daughters, were brought back to the Theban area, and the Valley of the Kings would be the obvious place."
The Valley of the Kings, near the city of Luxor in southern Egypt, was used for burials for around 500 years from 1540BC onwards.
The newly-found tomb is thought to date from the 18th Pharaonic Dynasty, the first dynasty of the New Kingdom which ruled between 1539BC and 1292BC and made its capital in Thebes, now Luxor.
It is the 63rd tomb to be discovered since the valley was first mapped in the 18th century, and was unexpectedly found only five metres away from King Tutankhamun's.
The team of archaeologists had not been looking for it.
"The excavation team was focused on the tomb of a 19th Dynasty pharaoh, King Amenmesses," Patricia Podzorski, curator of Egyptian Art at the University of Memphis, told the BBC's World Tonight.
"They were working in front of the tomb looking for foundation deposits possibly related to that tomb, and clearing away some workmen's huts from the 19th Dynasty that were both to the left and right side of the tomb," she explained.
"Underneath these workmen's huts, they found a shaft."
Four metres below the ground was a single chamber containing sarcophagi with coloured funerary masks and more than 20 large storage jars bearing Pharaonic seals.
The sarcophagi were buried rapidly in the small tomb for an unknown reason.
The discovery has come as a surprise to many, Ms Podzorski said.
"People have been saying the valley was done for 100 years," she said.
"They said it before Howard Carter found King Tutankhamun's tomb and they said it after. But, obviously, they are still wrong."