‘Once-in-a-century’ discovery made at Pompeii after lying under rock for 2,000 years

A ground-breaking discovery has been made in the ancient Roman city of Pompeii, almost 2,000 years on from being completely covered in ash.

The wealthy city had 10,000 to 20,000 residents in its hay day, though following the two-day eruption of Mount Vesuvius in 79 AD, it was preserved under a layer of ash.

Most residents were able to escape during the first phase of pumice rain - which lasted 18 hours - though over 1,100 bodies have been discovered on-site.

Many items from the time were found at the UNESCO World Heritage Site, along with preserved skeletons, such as coins, jewellery, and silverware.

More discoveries continue to be made at the site of Pompeii (Marco Cantile/LightRocket via Getty Images)

It may have been discovered in the 16th century, with excavations beginning in the 18th century, but more and more continues to be found out about the ancient area.

Archaeologists have now discovered a private bathhouse, which could be the largest in the city, featuring hot, warm and cold rooms, fancy artwork and even a huge plunge pool.

The Roman-equivalent of a spa, it is located in the middle of a grand residence that has been unearthed following an excavation over the past two years, as reported by the BBC.

Speaking to BBC News, Dr Gabriel Zuchtriegel, director of the Archaeological Park of Pompeii, explained: "It's these spaces that really are part of the 'Pompeii effect' - it's almost as if the people had only left a minute ago."

It is part of an entire block, featuring a laundry, bakery and a large private house, believed to be owned by one wealthy individual, potentially influential politician Aulus Rustius Verus.

"There are just a few houses that have a private bath complex, so it was something really for the wealthiest of the wealthy," Dr Zuchtriegel highlighted. "And this is so huge - it's probably the biggest bath complex in a Pompeiian private home."

The enormous bathhouse shows off the lavish side of Roman life (BBC)

The lucky users of the bathhouse would have changed in a vibrantly decorated changing room featuring a mosaic floor, making their way to the hot room, relaxing in the bath and enjoying its sauna-like warmth, before heading to the brightly-painted warm room.

Here, oil was rubbed into the skin before being scraped off - think of it as Roman skincare.

Then, they would enter the cold room, featuring red columns and a plunge pool big enough for 20-30 people to have a dip, as Dr Zuchtriegel said that it was popular to socialise and have some wine here in the summer.

Dr Sophie Hay weighed in on the complex as a 'once-in-a-century discovery', while also revealing the darker side of the Roman era.

A furnace would sit under the hot room, while a boiler room would also be located behind the hot room, with conditions being almost unbearable for slaves.

"The difference between the sumptuous life of the bathhouse, compared to the furnace room, where the slaves would be feeding the fire toiling all day," Dr Hay highlighted. "A wall is all that could divide you between two different worlds."

(CM Dixon/Heritage Images/Getty Images)

As the excavation nears its final weeks, more historical discoveries continue to be made. When it is done, it will be opened to the public to explore.

Two skeletons were also found in the house, with analysis of the pair revealing the shocking events following the eruption of Mount Vesuvius, as one of them, a woman, was holding onto jewellery and coins.

Trying to protect themselves in a small room, they were brutally killed as a mix of superheated volcanic gas and ash, also called a pyroclastic flow, made its way through Pompeii.

Despite all the discoveries made, a third of the city still lies underneath the volcanic debris, though this new excavation, the most extensive in years, has provided more information about Roman life.

The archaeologists have been followed by a BBC documentary team for a series called Pompeii: The New Dig, which is available to watch on BBC iPlayer.