We leave the Guatemala office at 6:30am sharp, and soon are off on the motorway to the coast. On the coastal highway, the countryside is emerald green, hilly and forested to the right, and a flat expanse of sugar cane plantations to the left. The sight of the volcanoes that surround Antigua is stupendous. From sea level, they look so much higher.

In Santa Lucía Cotzumalguapa, a small coastal town just north of the Pacific Highway, we sign papers to absolve the outfitter of any responsibility should we never be heard of again. Now is the time to chicken out. None of us do.

We continue down a rutted track ending at the riverbank, which is crowded with locals. This is the big event of the week. The outfitters come regularly with loads of rafters who disappear down the river and are never seen again. Next week, the same people are back with another load. Our guide, Tammy, hands out presents to the children, perhaps to keep them quiet so they won’t tell the police about these strange goings on.

The three rafts are inflated; we are assigned our places and issued life jackets and helmets. A quick instruction follows, during which we are informed that most people don’t know left from right, and back from forward. We scoff to think anyone could be so dumb. The boatmen will shout orders at us, such as “left forward” and “right backwards,” and we must paddle like mad in the direction indicated just like galley slaves, or get forty lashes. Looks like we are going to have lots of laughs!

We start off down the river ignominiously. People fall out of the rafts. The right side paddles forward when they should be paddling backwards, and vice versa. We wonder how we are ever going to finish the trip.

Amazingly we soon shape up, and learn all over again which is right and which is left. Several tributaries fill the river and it starts getting fun, though it isn’t exactly Discovery Channel, where half the time the rafts seem to be under water.

The river runs at the bottom of a shallow canyon, with the walls totally covered with vegetation. Birds and butterflies flit around us, and colourful flowering trees cling precariously to the banks of the valley. The sides are formed of smooth black volcanic granite, embedded with large pebbles and boulders. One can only imagine the cataclysm that caused this extraordinary feature. We drift down river, frequently going through mild rapids. At one point we stop and walk to a waterfall that pours from the rim of the valley. It’s wonderfully refreshing!

We stop at a small beach for a picnic lunch. While the crew sets up portable tables on the shore, and starts about making sandwiches and salad, we all get to socializing and swimming. By now, city slickers in our group, not used to more physical activity than it takes to sign a cheque or click a mouse, are beginning to feel the burn.

Off again after a well deserved rest, we soon hear a rumble, and round the next bend come to the most exciting rapids of all. The river foams and rushes like a jet from a fire hose between huge boulders. Unfortunately, there is a great tree trunk traversing the most awesome part. Had we continued through this rapid, we would probably all have been decapitated. So we haul the rafts out of the water and carry them around the obstruction.

Next, we spy a waterfall descending straight into the river. We take turns paddling our rafts beneath this impressive shower. Fortunately, we are using helmets, as the water cascades on you as hard as hailstones tumbling from the sky. As the river nears the coast, the canyon walls get less precipitous, and we can start seeing signs of civilisation. We can see sugar cane growing at the edges of the valley, and we pass under an unused railway bridge.

Finally we come to the end of the ride. It is 4pm. We have been in the river for 6 hours. Our arms seem to weigh 20 tons each.

As we are changing, we see a man cycle up to the far side. He stops at the edge, calmly takes off his clothes and wraps them in a bundle. He puts them on top of his bike, which he holds above his head, and proceeds to cross. On getting to our side, he dresses, wishes us all “Buenas tardes,” and continues blithely on his way.

We don’t need entertaining on the way back, as most of us are asleep as we climb back from the tropics to the temperate mountain climate of Guatemala City.