London - Five-year-old boys are not easily impressed - unless of course, you happen to be in possession of the latest toy superhero on the block.
But when I took my son to see his baby sister's swimming class, he couldn't believe his eyes. "Good girl - I'm so proud of you," he told her afterwards.
"When we get home, I'm going to find you a balloon." He had just witnessed 14-month-old Jojo being thrown in from the side, going underwater and holding on to the bar at the side of the pool.
Other babies were kicking to the surface; some were floating on their backs. One 13-month-old girl was able to launch herself into the water from a sitting position and then turn to hold on.
Infant swimming has become increasingly popular over the last 10 years, with babies as young as just a few weeks old being introduced to the water, and to potentially life-saving techniques.
Six months used to be the earliest point at which children were taken to the pool, but these days, it's widely acknowledged that in a properly chlorinated pool, there's no reason to delay, or wait until your child has completed their initial series of vaccinations.
Some of the babies who start early are able to propel themselves underwater before they can walk, or even crawl.
Strictly speaking, it's not swimming, but an introduction to eventually being able to swim on the surface of the water.
However, the majority of children who take the plunge early in life are much earlier swimmers. Some are able to do doggy paddle and swim around 5m by about 2,5m.
The "wow" factor apart, the safety aspect of introducing babies to the water as early as possible is the force behind infant swimming programmes.
Whether it's a puddle or a pool, children are fascinated with water, sometimes with frightening results: more than 100 children have died in water-related accidents over the last decade.
Lauren Heston, the founder of Little Dippers, has been running classes for 15 years.
"We like to say that by time your baby reached 18 months, if they fell in, hopefully they'd be able to turn back to the side and hold on," she explains.
"It happens younger, but some babies aren't quite so strong or co-ordinated. We aim to teach babies what to do in those first few moments. With an untrained baby they will fall in, and then, if they've never been underwater before, will probably panic and give up."
Dr Susan Childs, a neuropsychologist who has followed the Little Dippers programme with her own child, agrees with Heston that panic is a key factor in drowning.
"I think it's most important to help children to familiarise with the water so that they're less likely to panic. If you don't panic, you're less likely to drown."
Heston first became aware of babies' potential in water more than a decade ago.
"I used to be a diver in films and I worked on a commercial in 1989 for British Gas that had babies swimming under water.
"I was gobsmacked at what they could do: these babies, some as young as five months old, were swimming - or, rather, doing what they do underwater - in the sea on the coral reef with the fish and they were coping. I wanted to change career and went and studied with people that had trained these babies."
The Little Dippers programme uses word association ("ready, go", "hold on", "kick, kick, kick, kick"), repetition, and structured learning (incorporating songs and games) to build on babies' natural affinity with water and what is known as the dive reflex - a natural reflex that enables all of us to hold our breath when submerged, and which is particularly apparent in young babies.
But despite the huge popularity of classes such as Little Dippers and all the positive testimonies from parents (and babies), Heston does encounter criticism.
"Sometimes lifeguards say to me: 'You can't submerge babies, it's dangerous'. But what's dangerous is if you fall in a pond, and you've never been underwater before and you panic. That's dangerous, not what we do," she says.
But apart from life-saving potential, the programme is a really wonderful thing to do.
Dr Susan Childs emphasises the bonding benefits of taking your baby into the water. "You're encouraging your child in a very positive atmosphere.
"You're not focusing on the things they're doing wrong, you're constantly praising them and giving them a chance to feel that their parent values them in the best way possible."
Heston's methods may have raised a few eyebrows over the past decade, but so far, she's stopped short of a technique used by some Russian enthusiasts. "They make holes in the ice and mothers take newborn babies under it - it's supposed to make them amazingly physically strong. I've seen it!" she exclaims.
"Do you think I could do it in Clapham as the pond freezes over?" she laughs. "Do you think I'd get many takers?"
The funny thing is, I think she might. - The Independent