DALLAS CAMPBELL and Ellie Harrison have joined forces to travel the world in search of treasure.

As Harrison says: “Amazing tales of buried treasure do not just exist in story books or our imagination.

Our planet is full of treasure from precious metals to dazzling jewels.”

And Campbell adds: “All you need to know is where to look. Scratch the surface of our planet and you will discover a world of natural wonders. Our ingenuity has transformed them into priceless riches.”

As the series concludes, Campbell is in Florida Keys, braving vicious currents to dive on a shipwreck where, before now, 5,000 emeralds have been found.

“Perhaps the most intriguing treasures are those that have been lost. Storms, wars and misadventure have left millions, maybe billions of pounds worth lying at the bottom of the ocean,” he says.

“One of the interesting things about this area is that there are a lot of hurricanes and consequently the whole seabed is littered with shipwrecks, which is bad news if you’re the captain of one of those ships, but very good news if you’re a treasure hunter.”

He goes diving for treasure on one of the richest wrecks ever discovered.

“You have to cast your minds back, if you will, to 1622. The Spanish galley, the Atocha, was sailing from South America back to Spain via Cuba, completely loaded with treasure, and about 90 miles off the Cuban coast, she got hit by a hurricane and was sunk,” he says. “What is left of the Atocha was rediscovered in 1985. The galleon has been destroyed by the ocean but around £240m worth of booty has been discovered, strewn for miles across the sea floor.”

Meanwhile, Harrison finds herself in Russia, where she tells the tale of obsession surrounding a jewelled room, decorated with millions of pounds worth of amber. She also chats with diamond-cutters, who reveal the pressure they are under – one slip of the hand could cost them millions of pounds.

She also travels to Egypt, where she stares at Tutankhamun’s death mask, one of the most famous golden images on the planet, while Campbell hunts for a treasure chest hidden in the Rocky Mountains and comes face to face with China’s Terracotta Army.