Cenotes
I am sitting in the back of a jeep travelling from the Mexican town of Tulum to a local cenote. Cenotes are inland freshwater sinkholes. These natural phenomena are unique to Mexico’s Yucatan Peninsula and a few neighbouring Caribbean islands. They are popular with tourists for sightseeing, snorkelling and diving; the activity which has brought me here today.
The diving instructor, a bandana clad Chilean by the name of Rodrigo, holds the steering wheel with one hand whilst he bangs the other against the side of the jeep in time with the heavy metal music resonating through the vehicle. The frenetic drumming only serves to increase my apprehension. My concern is that the majority of my very limited diving experience has consisted of floundering around at the bottom of suburban swimming pools. This dive will be to forty five metres.
Turning off the main road we proceed to bump along a jungle track and are soon pulling to a halt in a small parking 
area adjoining a cenote known as The Pit. As I clamber out of the vehicle, my Swedish diving companion Lars, whose acquaintance I made earlier that morning also confesses to feeling nervous. I enquire as to why.
‘I am an inexperienced diver,’ he replies. ‘I have only dived forty two times. How many dives have you done?’
‘Five.’
After peering into the dark ominous waters of the cenote (see picture), I begin to hurriedly assemble the diving equipment, as Rodrigo outlines The Pit’s sinister history. During Mayan times The Pit had been used for human sacrificial purposes. He stops speaking suddenly and looks severely in my direction.
‘What?’ I ask somewhat defensively.
‘Your tank, it’s the wrong way round.’
Within a minute Rodrigo and Lars have reassembled my diving kit correctly and I am intrepidly approaching the cenote, along the very same path used by countless Mayan sacrificial victims.
Five minutes later – Clasping our torches in one hand we begin our descent. I feel somewhat calmer now. It is as if the cool waters of the cenote have had a therapeutic effect. Lars and I look around in awe at the rock formations that surround us. Some thirty metres later we reach a cloud of sulphuric acid air bubbles and our visibility becomes minimal. Attempting to remain calm, I follow the beam of light being emitted from Rodrigo’s torch and within no time we have passed through it.
At forty five metres we stop and Rodrigo points out some fragments of human bones with his torch. Until recently there were actual skulls here; but the actions of one plundering diver have resulted in the skulls being taken to an archaeological museum.
Rodrigo points towards my pressure gauge, to enquire as to how much air I have left. I stare at the gauge in disbelief; for I cannot comprehend how the reading is only a hundred and ten. We had been informed that we should have a reading of nearly two hundred when we begun our ascent. For a terrifying moment I wonder if I too will be making a contribution to the collection of bone fragments. On the trip up Rodrigo gives me oxygen from his spare regulator. This action results in him having to stop to take breaths from an air hole in the rock.
An hour later – Both Lars and I are relaxed on reaching our next destination, a welcoming cenote with a wide welcoming entrance and transparent waters (see picture). The dive will be to about twelve metres; merely the depth of a couple of suburban swimming pools.
