Humpback whales are incredibly majestic animals that inspire awe in anyone who sees one.
Believed to be among the most intelligent creatures after humans, they are beautiful and mysterious.
To actually swim with one is life changing.
These lucky people were swimming in the waters of Tonga, hoping to see these magnificent whales in their own habitat.
They didn't expect to be so close as a gigantic male rocketed upwards and exploded through the surface in a spectacular breach.
The incident was thrilling, and a little unsettling at the same time as this 50,000kg giant was not far away from the swimmers when le leaped in the air and came crashing down again.
The true enormity of a whale cannot be fully appreciated until you see one from such a close vantage point.
One of the swimmers captured the footage on his GoPro as he was watching another whale below.
The second whale appeared on his left and was obviously heading up to breach.
The fish eye lens of the GoPro makes the whale appear to be farther away than he actually was.
The camera man lifted the camera out of the water and then plunged it back under the surface again in order to capture the entire event.
As the group exchanged looks of astonishment and wonder, they yelled and cheered with excitement over what they had just witnessed.
Humpback whales travel from all over the planet, arriving in Tonga for breeding and mating.
It is one of the few places on earth where the calves are safe from killer whales, their most common predator.
The whales eat krill in the colder waters, storing up their fat reserves for the long migration to these tropical waters.
They do not need to eat while they are here.
Females will spend several months nursing their calves until they are large enough to make the journey back to their feeding grounds at the end of the year.
Humpback whales have been declining in numbers in the last two centuries.
Whaling for commercial products and oils, as well as increased interference from shipping have taken a huge toll on the populations around the world.
Losing these magnificent animals forever would be beyond tragic.