A staffer of an English historical organization stumbled upon evidence that might answer one of Stonehenge's mysteries due to a hose pipe that failed to water some parts of the site.

For years, archaeologists attempted to determine if Stonehenge was once a full circle or if it has always been an incomplete ring.

Tim Daw, custodian at English Heritage, described the brown spots that he noticed after a short hosepipe failed to water those particular parts. He observed that the patches, which appeared last summer, overlap with the locations where previous researchers had looked for traces of stone holes. The researchers first saw these marks in July.

"I called my colleague over and he saw them and realized their possible significance as well. Not being archaeologists, we called in the professionals," Daw told The Guardian.

The experts quickly took aerial photos of the stone monument because the forthcoming rains might erase the brown spots. The researchers also mapped the scorch marks seen in Wiltshire's western side. These brown patches were indeed located at where stones could have stood to make the site a perfect circle.

Senior properties historian for English Heritage Susan Greaney regarded the discovery as a significant event as it might lead the researchers to the location of the missing stones.

 "If these stone holes actually held upright stones then we've got a complete circle," Greaney told BBC News. "It's really significant, and it shows us just how much we still have to learn about Stonehenge.

No plans were made yet on the excavation of the brown marks.

Stonehenge is an ancient monument of standing stones in England. Archaeologists believe that it might be built between 3000 and 2000 B.C. and completed between 2400 and 2200 B.C. Early theories suggested that it might have been used as a burial ground and some religious activities. 

Further details of the study were published in the Sept. 2 issue of the journal Antiquity.