He also walked them round to an area where the ancient Maya used to play ball games.
As they began the trek up to the top, the couple paused to peer into the ruins, asking their guide questions.
They stopped at the halfway point to admire the view, posing for pictures before turning to continue the climb.
But the Duke got the giggles when he found himself face to face with another group of photographers positioned behind them.
‘We got one [group] one side and another the other. You are in each other’s photographs,” he laughed.
Mr Moore told them: “People often like to try and run up here.”
The Duke was shocked. “What they race?” he asked. “You must be very fit if you are doing this three times a week, Allan.”
Caracol was discovered by a Belizean logger in 1937 when the country was then British Honduras.
Archaeologists spent several decades excavating it, discovering monuments, tombs and extensive terrace systems.
The Caana is believed to have been built so that high priests and rulers could be closer to the sky.
Asked how Belize felt about the British monarchy, Mr Moore said: ‘It’s as relevant here as it is in the UK. It’s Symbolic and we respect that. And some people like having a monarchy far, far away.
“As an archaeologist, I cherish what is rare. As a good Belizean, I welcome the prince and his wife. We are known to be a hospitable nation. They will enjoy this.”
Masterclass in catching a monkey
The Duke and Duchess were later taken on a survival masterclass, taught how to catch and kill a monkey and catch a turkey deep in the Belize jungle.
The couple trekked into the undergrowth to be greeted by British and Belizean soldiers working side by side at the British Army Training Support Unit (Batsub).
It was a return visit for Prince William, 39, who spent three weeks at a specialist unit in 2000 during his gap year before university. He was also reunited with his former academy sergeant major at Sandhurst who now runs the jungle unit.
The couple were shown how to boil water using a plastic bottle dangling over a fire, fashion a bamboo tree to use as a pressure cooker and sharpen a bamboo spear to create a medieval type weapon to trap and kill monkeys and birds to eat.