Boston: The Great Pyramid of Giza, one of the Wonders of the Ancient World, is not perfectly built, say scientists who found that the structure's base is slightly lopsided.

Researchers surveyed the oldest and biggest of the three pyramids at the Giza pyramid complex, and discovered that the pyramid's west side is longer than the east side. The discrepancy is just a few inches but the difference was enough for the researchers to detect.

The pyramid was originally clad in hard, white casing, but much of the casing stones are now gone. Without them researchers have had difficulty getting the precise measurements of the pyramid when it first stood.

In an attempt to know the original lengths of the pyramid's sides, researchers from the Glen Dash Research Foundation and Ancient Egypt Research Associates (AERA) in the US looked for marks that indicate the original casing baseline of the pyramid or points where the casing stones once touched the platform.

They eventually found 84 points along the edge of the pyramid with evidence of the building's original baseline. A statistical analysis showed that the pyramid's east side originally measured between 755.561 and 755.817 feet. The west side, on the other hand, was found to be originally between 755.833 and 756.024 feet, the 'Tech Times' reported.

It is possible that it was the result of mistakes committed by builders during construction, researchers said. Because the west side was 5.55 inches longer than the east side, it means that the pyramid was not a perfect square.