'We found a 200-year-old bottle of wee'

This beautiful bottle has been hiding some secrets

You may have heard of a message in a bottle, but do you know about the mystery in a bottle?

It all started when what looked like a pirate's bottle was found upside down, preserved in mud, on a building site in the town of Cleethorpes in Lincolnshire.

The intriguing item was delivered to the University of Lincoln for further investigation.

While at first, the builders on the site thought it was something they may be able to drink, luckily they didn't as it turned out to be filled with... WEE!

How was the wee discovered inside the bottle?

Zara Yeates has been doing some smashing work investigating what's inside the bottle

After almost a year of carefully drying out the object, University of Lincoln student Zara Yeates began to look at what could be bottled up in there.

Zara told BBC journalists Simon Spark and Stuart Harratt that she used a combination of techniques to discover its age and what it contained.

Soon the bottle started to spill its secrets - Zara learned that its shape was introduced in 1790 and its unevenness suggested it was made by hand.

Zara said: "We reckon this is probably about 200-years-old, on average. So the fact it's still got the liquid in it after 200 years is very unique."

The university student then used a special scanner called a multi-spectral imager, which throws different types of light onto an object.

Zara explained: "We used a preset for bodily fluids and it's the only thing that showed the liquid through the bottle."

This revealed what was inside was mainly urine.

Why was the bottle filled with wee?

There are different theories about the wee in the bottle - including a superstition wishing sailors safe travels at sea

It all comes down to the history of unusual superstitions.

Zara believes it could be a bottle to ward of witches.

"People would fill bottles with urine and they'd be put in an opening to a house to stop spells," she explained.

Another theory is it was put there by a superstitious sailor hoping for a safe trip at sea.

Josephine McKenzie, senior technician in the university's Conservation of Cultural Heritage department, said it was rare to find a bottle this old completely intact.

"We often get a lot of ceramics, a lot of textiles, but we very rarely get glass especially something like this," she said.

Un-pee-lievable!