Sudan pyramids: Archaeologists explore the waters below

Sudan has more pyramids than Egypt, as its tourism ministry is always keen to point out, and in the ancient royal burial site of Nuri many Nubian pharaohs were laid to rest.

There's only one problem with this incredible site: the rising groundwater is making it hard to get into many of the pyramids.

Pearce Paul Creasman, an underwater archaeologist, used his expertise to explore some of them, and as he told BBC World Service's Newsday programme, he discovered a tomb with quite a surprise.

The excavation was supported by the National Geographic Society.