Antonio Llufriu and his group, Underground Explorers C9C, travel far into the darkness, exploring abandoned mines and caves that have often never been touched.
Their images showcase an array of awe-inspiring wonder – from gigantic, empty cavernous spaces to tight passageways that members of Underground Explorers C9C must squeeze through in order to discover such gems.
The majority of their work is carried across England's Peak District and across Wales.
Antonio, 43, who lives in Chapel-en-le-Frith, England, said: "The most fascinating thing about exploring caves and old mines is that they are spaces that have remained untouched for many decades, centuries and, in the case of new caves, they have never been touched.
"Once you step inside them, time stops and you become fully present and alert with your senses – there is no other feeling like it."
When shooting such vast spaces Antonio and the team try to showcase an element of atmosphere and scale, too – often including fellow cavers in their images.
Underground Explorers C9C is made up of individuals with a range of expertise in fields suitable for caving adventures – such as photography and rigging, engineering, cave diving and surveying.
Though the team bring together these expertise, there are a number of dangers that present themselves while caving, especially in disused mines, Antonio said.
Some of the hazard that can present themselves include hypothermia, rock falls, exhaustion and low oxygen levels.
Antonio said: "The safety procedures we use are very well known in the cave and mine exploring communities.
"First, you wear adequate clothing and protective equipment; then plenty of light and spares just in case.
"We also carry a first aid kit and have a person outside as the 'call out,' who will alert cave rescue if we are not out of the cave or mine by a certain time.
"In some particular mines, we even have a box of supplies, just in case."