Scientists have discovered a hidden corridor nine meters long near the entrance of the 4,500-year-old Great Pyramid of Giza.

The corridor could lead to further findings and is believed to have been built to redistribute the pyramid’s weight. Five rooms atop the king’s burial chamber are also thought to have been built for the same purpose. The discovery was made using non-invasive technology such as infrared thermography, 3D simulations, and cosmic-ray imaging.

In 2017, researchers announced the discovery of a 30-meter long void inside the Great Pyramid, the first major inner structure found since the 19th century.