A tiny robot has made a momentous archaeological discovery deep under the famous Temple of Quetzalcoatl, near the Pyramid of the Sun in Mexico, it was announced on Monday.

Experts expected to find just one ancient chamber at the end of a stretch of 2,000-year-old unexplored tunnel at the Teotihuacan site. Instead, the remote-controlled vehicle has beamed back images of three mysterious caverns.

The three-foot-long investigator, named Tlaloc II-TC after the Aztec god of rain, was first lowered into the depths of the pyramid to check it was safe for human entry.

The temple is best known for the towering Pyramids of the Moon and the Sun.

The complex of pyramids, plazas, temples and avenues was once the center of a city of more than 100,000 inhabitants and may have been the largest and most influential city in pre-Hispanic North America at the time.

But nearly 2,500 years after the city was founded – and about 2,100 years after the Teotihuacan culture began to flourish there – very little is known about the identity of its rulers.

No depiction of a ruler, or the tomb of a monarch, has ever been found, setting the metropolis apart from other pre-Hispanic cultures that deified their rulers.

More information, photos and video can be found here.

A new satellite survey of Egypt has discovered 17 lost pyramids.  The work has been pioneered at the University of Alabama at Birmingham by US Egyptologist Dr Sarah Parcak.  The BBC report that more than 1000 tombs and 3000 ancient settlements were also revealed by the infra-red images.  The satellites orbited 700km above the earth and were equipped with cameras that are able to pin-point objects less than 1m diameter on the earth’s surface.  Following the observations, test excavations took place:

Ancient Egyptians built their houses and structures out of mud brick, which is much denser than the soil that surrounds it, so the shapes of houses, temples and tombs can be seen.

“It just shows us how easy it is to underestimate both the size and scale of past human settlements,” says Dr Parcak.

And she believes there are more antiquities to be discovered:

“These are just the sites [close to] the surface. There are many thousands of additional sites that the Nile has covered over with silt. This is just the beginning of this kind of work.”

• The full article and details of  the ‘Egypt’s Lost Cities’ broadcast can be found on the BBC website.