From his explorations around the world, Sir Ranulph has been able to embrace a variety of cultures and see at firsthand how vulnerable our nature and climate is to mankind.
Although stating he is no expert on business Sir Ranulph said: "It is very, very important that every side of the environment is kept as pristine as is humanly possible, and ecologically we have done an awful lot of damage. We just have to hope that we can put quite a lot of it right in time before any particular brand of animal, or fish, or bird disappears all together."
In terms of his encounters with big fish, Sir Ranulph said the biggest fish he has ever come across was a giant Nile perch near the Ripon Falls in Uganda, during his journey up the Nile which he completed in a hovercraft.
Sir Ranulph also recollected his awful memory of mackerel during his expedition around the world.
"A company in London gave me 2 tonnes of mackerel to feed 52 people aboard a boat for three years, and the refrigerator broke down.
"It was a 40 year old ship in the tropics, and the mackerel were all turned to mush, and the mush went into the bilge system and we smelt rotten mackerel for three years."
Enough to put anyone off eating mackerel, Sir Ranulph said that thankfully he is much more of a salmon and sardine man.
Sir Ranulph has taken part in 18 expeditions to date. Yet, of all his adventures and experiences, the most memorable moment for Sir Ranulph is one much closer to home which he shared with his late wife, Ginny Fiennes, after returning to the UK from a three year expedition travelling vertically around Earth from Greenwich to Greenwich.
After spending three years never moving any faster than 12 miles an hour, being driven round Hyde Park corner by his late wife at great speed in the London traffic was a truly terrifying experience, Sir Ranulph reflected.
At 71 years of age, Sir Ranulph Fiennes has just completed yet another marathon for which he broke the record for being the oldest Briton to complete the race.
Running 156 miles in just six days in the scorching 50 degree heat through the Sahara Desert for the Marathon des Sables, Sir Ranulph joked, "there were no fish on that trip, only camels".
As well as being able to break records, Sir Ranulph's expeditions so far have helped raise a staggering £18 million for UK charities.
Enjoying the competitiveness of his challenges, Sir Ranulph has no plans to stop just yet, and has another trip in the pipeline, which he cannot reveal just yet, in aid of Marie Curie Cancer Care.