Europe may seem like an unlikely place to find an ancient pyramid, but a group of scientists believe they've found one -- or possibly three -- in Bosnia.

Scientists investigating a hill near the town of Visoko said it matches the triangular dimensions of similar structures in Latin America, with the same flattened top.

It also has 45 degree slopes and corners matching the four points of the compass.

The precise shape of the hill, called Visocica, seems to indicate that nature had little to do with its formation. Satellite imagery also revealed two other similar mounds in the Visoko Valley.

"In the lack of other processes that would affect their existence, we consider them to be anthropogenic structures," geophysicist Amer Smailbegovic told a news conference.

If the scientists are right, the pyramids will be the only ones found in Europe. Bosnia would join other countries famous for the ancient structures, like Egypt and Mexico.

In fact, archeologist Semir Osmanagic said the suspected pyramid hidden underneath Visocica is even larger than one of the most well-known pyramids in the world.

"(The) Bosnian 'Pyramid of the Sun' ... is the highest known pyramid with a height of 220 metres," he said.

"It is about 80 metres highter than the Great Pyramid in Egypt."

Visocica itself measures 650 metres in height, but digging into the hill, the scientists said they hope to find stones marking the surface of the pyramid, explaining the smooth 45 degree slopes.

They have already found what they think is a man-made tunnel system.

"The notion is that the tunnel connects all the pyramids in the valley, and now we are at the start of the mapping and excavation process of the tunnel," said Osmanagic.

The first to enter the tunnel entrance was a group of rescue workers from a local coal mine, who explored the network on Friday. They travelled about 260 metres and found two intersections.

Experts from Egypt are scheduled to join the scientist in May.

Visocica is located about 30 kilometres northwest of Sarajevo, Bosnia's capital.

During the Middle Ages, Visoko was Bosnia's capital. Experts say human settlements existed in the Visoko Valley 7,000 years ago.

With files from CTV's Tom Kennedy in London and The Associated Press