Archaeologists from Cairo have discovered two tombs in Egypt dating back more than 3,000 years.

The tombs, found on May 8 just 15 miles south of the Giza Pyramids, are 3,100 years old and are helping archaeologists further understand ancient tomb design.

See also: Scientists Discover Clever Trick Ancient Egyptians Used to Build Pyramids

A team of Polish missionaries and archaeologists from Cairo University discovered the tombs in Saqqara, which is “considered the richest archeological city in Egypt,” according to Al Arabiya News. The team has been at Saqqara for more than 12 years.

An Egyptian conservator works at a newly-discovered tomb dating back to around 1100 B.C. at the Saqqara archaeological site, 30 kilometers (19 miles) south of Cairo, Egypt, Thurs., May 8, 2014. Image: Amr Nabil/Associated Press

The two tombs are empty except for their burial chambers, which were still decorated with carvings and colors. They used to contain the bodies of high-ranking officials Pah Seir and Ptah Ms.

One inhabitant was part of the guard of the army archives and the other a royal messenger to foreign countries. Both were alive and served during the 20th dynasty (1189 to 1077 B.C.).

An Egyptian conservator cleans limestones at a newly-discovered tomb dating back to around 1100 B.C. at the Saqqara archaeological site, 30 kilometers (19 miles) south of Cairo, Egypt, Thurs., May 8, 2014.

Both tombs show design and architectural similarities of ancient Egyptian temples. But what makes the discovery truly unique is what it means about Saqqara.

“It proves that Saqqara, a necropolis, known as a burial place for Old Kingdom Pharaohs, was also used by the Pharaohs of the New Kingdom," said Abdel Halem Nour El Din, former heard of Egypt’s Supreme Council of Antiquities to The Cairo Post.

These aren’t the first tombs found in Saqqara and probably won’t be the last as Saqqara, is home to many excavations, including the oldest pyramid in Egypt. Archaeologists also recently found the tomb of Baser, the royal messenger of a pharaoh also in the era of the New Kingdom. The royal messenger’s tomb covered in decorations and carvings, like his wife crying at his tomb, according to Circa.

Archaeologists and journalists gather at a newly-discovered tomb dating back to around 1100 B.C. at the Saqqara archaeological site, 30 kilometers (19 miles) south of Cairo, Egypt, Thurs., May 8, 2014. Image: Amr Nabil/Associated Press

Renovation of the tombs will begin soon and may be open to the public by October.