If you've ever had a tour of the tunnels or caves in Gibraltar, there is a very good chance your guide was Pete Jackson.
Since he arrived in Gibraltar in 1989, he has shown more than 3,000 people around some of the Rock's most mysterious sights - including members of the Royal Family.
But how did this 60-year-old man from the North of England come to call Gibraltar his home?
Born in 1961, Pete grew up in Scarborough and as a schoolboy would explore the caves in North Yorkshire and Derbyshire.
Pete, who now works as a freelance guide in Gibraltar, explained: "My Environmental Studies teacher was really into caving, so we had some great trips away. Some of his friends were in the Cave Rescue Team, and, when it was safe to do so, they would take kids from our school with them."
Then at the age of 15, Pete joined the army as a Junior Gunner in the Royal Artillery.
And after two years of intense basic training that "turned me into a soldier", he went off to serve the Queen in the German cities of Paderborn and Dortmund, also serving tours in Northern Ireland.
Pete met the love of his life Lesley while on leave in Scarborough in 1981. They married in 1983 and have three children: Peter, Rachael and Georgina.
After 12 years in the British Army, Pete, who learned to speak reasonable German during this time, came to Gibraltar in 1989, to instruct on an Air Defence Missile system to the Gibraltar Regiment.
But it was also love at first sight for Pete when he first saw Gibraltar.
"My mind was blown away during the landing," he recalled.
"The aircraft circled the Rock twice and I fell in love with it before it touched down.
"I tell everyone, you can't step in a puddle here without it oozing military history through your toes - and I got caught up in it."
Shortly after leaving the Royal Artillery in 1991, he joined the Gibraltar Regiment (as it was then called) at age 30.
"During the first Mess Dinner, I was sat next to a Sergeant called Tito Vallejo (a very prominent cave and tunnel guide). We got talking and he invited me to a tour of Lower St Michael's Cave the next morning. I was mesmerised."
In 1994, Tito left the regiment, and Pete took over from him as Chief Tunnel Guide for the Ministry of Defence, a position that he held for the next 17 years.
He continued: "It was not my main role though; it was a second hat, something I did for the love of it.
"I adore what I do; I'm probably a little too passionate about it; it does give me a lump in my throat."
So what is it exactly that Pete loves about his job?
He replied: "A lot of it, especially the military history side of it, is the sacrifice that's gone on here. The number of people that have laid down their lives in the defence of the Rock, and to try and win it. It's important to those servicemen who have fallen in battle that that is recognised and understood by the present generation. That's what keeps me motivated to do what I do."
When asked what was his favourite location to show people around, Pete replied without hesitation: "The Northern Defences."
As to why, he said: "Because it's been manned on a military footing since the Moors carried spears. This is a serious defensive location, you can stand in a position and know that a Moorish soldier stood there in 1309 defending it against the Spanish, followed by Spanish soldiers, who stood there in 1333 defending it against the Moors. In 1704 the Anglo-Dutch came and they took it. Soldiers have been manning the same positions from 711. By World War II you've got the Brits covering the same arcs with a machine gun rather than a musket."
Pete does have spare time for other interests, however: he has a passion for motorbikes, which he has three of.
He's also on the board of trustees for the Gibraltar Heritage Trust and spends many weekends restoring artillery pieces around the Rock - the latest being Lord Airey's Battery, which, according to Pete, is in dire need of attention.
The artillery battery, which was completed in 1891, is found in the Upper Rock Nature Reserve and has commanding views over the Straits and the waters surrounding Gibraltar.
As for famous faces he's shown the inside of the Rock, Pete recalls Princess Anne being one of the most interesting.
"She was very astute," he said.
"She asked more questions than you can imagine and was interested in tunnel warfare and how you could clear a tunnel system of an enemy. She wanted to know every little piece of information."
His encounter with the member of the Royal Family was the precursor to a funny anecdote with Prince Charles, who presented Pete with his Member of the Order of the British Empire (MBE) in 2005.
Pete, said: "When it was my turn, I was chatting with Prince Charles, and he made me feel very comfortable in his company. He asked me if we were keeping the Rock in British hands? And I replied: 'Just about Sir.' He then asked me if I was still conducting tunnel tours, to which I replied: 'I am Sir, ooh and I took your sister in there last year!'
"I suddenly thought, 'Oh sh*t, I shouldn't have said that, I should have called her the Princess Royal!' He replied 'Really? Nice to meet you.'
And that was it! He made the gesture for me to leave! Looking back I was so embarrassed, but I suppose it was a funny moment."
Pete added that he received his MBE for Services to Gibraltar.
He explained: "I have worked with a lot of veterans and helped to show them where they used to work. I have also helped in finding where people's relatives have died in some cases placing memorial plaques at the spot. It is very rewarding."