Satellite radar maps a 2,600-year-old mudbrick complex beneath Egypt's Nile Delta

The find opens a layer of the Nile Delta that digging could not reach. The older deposits sit below the water table in waterlogged clay. What the building was remains unresolved. The team has dug only a small pit so far.

A 128 by 62 metre anomaly under Kom C

Sentinel-1 radar images showed an oval anomaly beneath a mound known as Kom C at Tell el-Fara'in, about 85 miles northwest of Cairo. It measured 420 feet long and 203 feet wide, or 128 by 62 metres.

To test what the radar suggested, the team ran electrical resistivity tomography (ERT) along 15 parallel lines across about 5,400 square metres, or 58,100 square feet. The method sends currents through the ground. It measures how different materials resist them, producing a cross-section without a trench.

The survey produced a layered picture. From the surface to 3 metres down, the survey found displaced mudbricks, pottery shards and broken limestone from the Ptolemaic and Roman periods. That debris points to centuries of rebuilding on the site. The survey found a large mudbrick structure between 3 and 6 metres down. It dates to the 26th dynasty, also called the Saite period, which ran from 688 to 525 B.C. That makes the building roughly 2,600 years old.

A joint team published the work in the journal Acta Geophysica. It came from Egypt's Kafr El Sheikh University and Durham University in the UK.

Why a satellite did the digging

Occupation at Buto ran from around 3800 B.C. to the Early Islamic era of the 7th century A.D. Each period built over the last.

Sentinel-1 sends microwave pulses down from orbit and measures how they reflect back. The returning signal carries subtle differences in surface moisture, elevation and reflectivity that can hint at structures buried underneath. The constellation's radar probes were launched between 2014 and 2025.

The researchers wrote about combining geophysical measurements with remote sensing. They said it gave "a very accurate vision in detecting buried settlements in a complex region". They added that 3D inversion algorithms were "particularly effective in delineating buried mudbrick walls and architectural structures".

The sand layer under the walls

At 6 to 7 metres down, below the mudbrick structure, the survey hit a thick layer of clean sand. The team reads it as an artificial foundation. It is a sandbox laid down to spread the building's weight over clay that swells when wet and shifts as it dries.

The team dug a 10 by 10 metre pit 6 to 7 metres deep. It confirmed the resistivity model. It uncovered mudbrick walls resting on the sand, plus amulets depicting Egyptian deities including Wadjet and a small offering basin.

The authors list a large tomb, a shrine, a priestly residence or a religious service complex. Hussein Bassir is director of the Antiquities Museum at Bibliotheca Alexandrina. He said the sand cushion showed the builders "profoundly understood their environment".

What the site was

Buto is modern Tell el-Fara'in. It was the sacred home of Wadjet, the cobra goddess of Lower Egypt, and one of the most important religious cities of the pharaonic period. The city was largely unoccupied for roughly 1,500 years before it was resettled. Ptolemaic remains at the site date from 305 to 30 B.C., and Roman material from 30 B.C. to A.D. 395.

What happens next

The team plans to expand the non-invasive surveys with larger equipment. The aim is to reach deeper, older levels of the settlement. The study says another temple may remain buried under a thick clay layer. That is in addition to the known temple at the site.