A trip to Cartagena, in the Colombian Caribbean, called for a volcano mud bath for Lucy followed by an exploration of this ancient town and a night medallions, throbbing music and salsa madness.

Did I really want to dive head first into a thick, grey soup the consistency of condensed milk? Looking down into the pale sludge I began to have second thoughts about taking a mud bath in the top of a volcano.

“It’s between 1000 and 2000m deep,” Don informed me peering over the of the crater. “Great, a bottomless pit full of slime. Are you sure it won’t suck me down into the bowels of the earth?” “Trust me,” replied Don, “you’ll love it.”

Don had been travelling for 22 years and had just spent six months down a Bolivian mine in Potosi. If I was going to trust anyone it would be him. From the top of the track the volcano looked like a large ant hill rising up beside the lime green lake. People climbed up one side and down the other, metamorphosed by the bog.

Volcan del Totumo is a miniature volcano about an hour’s bus ride from Cartagena on the Colombian Caribbean. Spewing up mud instead of lava and ash, the legend claims that the volcano used to breathe fire, but a local priest, thinking that it was the work of Satan sprinkled it with holy water extinguishing the flames and turning the insides into mud to drown the devil.

Mud volcanoes exist all along the Caribbean coast of Colombia, some just bubbling fissures in the ground, but El Totumo is one of the largest in the world, standing at 15m high.

Mud volcanoes are created by sulphurous gas emissions from decaying vegetation underground. The gas pushes the mud up through the ground forming a conical mound. The volcano continues to grow as long as more mud is being forced upwards over the rim of the crater. I had climbed the rickety steps to a makeshift wooden platform where I stood eyeing the mud bath warily. The mineral-based mud is supposed to have therapeutic properties but I wasn’t convinced.

“Don’t be such a coward.”

Taking off my sarong I edged towards the mouth of the volcano. The ladder down into the crater was slippery with a fresh coating of sludge. I let go and arms pulled me into the centre. The mud was warm and smooth and smelt of sulphur.

Floating on a dense mass of slime, rolling over and lying on my back in the mud, I felt like a hippopotamus in heaven. Don did a somersault in slow motion as a monster from the deep started to knead my shoulders and I relaxed into the glutinous ooze.

“Are they really masseurs or is he just having a grope?”

Nobody seemed to be objecting.

Clambering down the side of the volcano I squelched over to the lake where local women were waiting to wash away the hardening crust. We waded out into the shallows and I knelt in the warm water while a 12-year-old girl, laughing and singing, scrubbed away the slime.

Rinsed clean, but still smelling slightly of bad eggs, we caught a lift to Cartagena in the back of a pick up truck. “They missed a bit,” said Don scooping a globule of caked mud out of my ear as the walls of the old city came into view.

Cartagena de Indias was founded in 1533 by Pedro de Heradia and soon became the main Spanish port on the Caribbean coast. It was from here the gold plundered from the Indians by the conquistadors was stored until it could be taken back to Spain by galleons. As a result the city became prey to pirate attacks from buccaneers like Sir Francis Drake, and walls and outlying forts were constructed to protect the port from marauders.

South of the old town is an L-shaped peninsula where the modern resort of Boccagrande has been built. A beach lined with high-rise hotels and populated with street sellers carrying shell necklaces and buckets of clams caters to the Colombian tourists.

I was staying in the Hotel Holiday, on Calls Media Luna, a street full of cheap hotels and brothels in the seedier part of the old town. Situated around a thin secluded courtyard, it was full of English travellers, and it was there that I had picked up Don.

The old town was a maze of cobbled alleyways, plazas, shady courtyards and churches bathed in an intense light and colour.

Wandering through the main gateway I crossed the Plaza de los Conchos, the old slave market surrounded by traditional balconied houses, and made my way through the Plaza de in Aduana, past the statue of Christopher Colombus, to the Church and Convent of Son Pedro Clever.

Saint Pedro Clever was a 17th Century Jesuit priest who used to beg for money to give to the slaves. He was nicknamed the “Apostle of the Blacks” and “Slave of the Slaves” and was the first person to be made a saint in the New World. His body is displayed in a glass coffin under the altar in the church.

The convent, a peaceful white three-storey building around a cool, green tree lined courtyard inhabited by macaws and toucans, is a retreat from the oppressive heat of the streets.

Each shaded square and colonial mansion in the old town is coated with history, from the Plaza de Bolivar with its statue of Simian Bolivar, “The Liberator”, who led the struggle for independence against Spain, to the Palacio de la lnguisicion, where 800 people were condemned to death and executed. Their supposed crimes ranged from witchcraft to blasphemy.

Cartagena isn’t languishing in the past though. The air is heavy with an intoxicating mixture of post and present. Meandering through the steamy streets, past men lolling in doorways and mongrels skulking in the gutters, tactile harassment and machismo permeate every encounter as the odours of the Caribbean stick to your skin.

Back at Hotel Holiday, Don had been polishing his Jesus sandals and was ready for a hot night of salsa. He had obviously been underground for far too long. Starting in the lively square of Santa Domingo, we drank a carafe of red wine at one of the tables clustered in the shadow of the church, before moving on to a bar on the city walls where we watched a group of obese Americans dance the meringue.

Then it was time for hard core Cartagena. In the heaving salsa bar thrust up against Don’s medallioned chest, the whole building seemed to throb with the beat as he swung me madly around the floor.

Escaping on to the crowded balcony for a breath of the still sultry air I looked out over the floodlit city walls. A large Caribbean man with beer-belly ballooning over his trousers offered me a swig from his bottle of rum. Clutching his heart, he started rolling his eyes expressively to reveal his total adoration.

Out of the corner of my eye I saw Don bearing down on me again. Taking another shot of burning rum I felt the rhythm seep under my skin. Cartagena was in my blood. Infected and delirious I prepared to salsa through the clammy night.