At more than 13,000 feet above sea-level in the Andes, we were as close to heaven as most mortals can hope to get – and closer to hell than anyone would want to be.

A group of miners steadily chewed coca leaves, mixing the wad with ash. They claimed it immunized them against cold and hunger. Armed with carbide lamps, most not wearing safety helmets, they began to file into the mine, ducking to avoid broken timbers, crawling through puddles.

I thought about the dark stains smearing the mine entrance. They were from the blood of the llamas ritually sacrificed to appease El Tio, the devilish deity who rules underground.

Coca juice numbered my mouth and claustrophobia gnawed at my stomach. My heart thumped with the exertion at this altitude. What the devil was I doing here, deep in the depths of Cerro Rico (rich hill), the mountain that broods over Potosí in Bolivia?

The astounding wealth below the surface of the cone-shaped hill, called Sumac Orcko ("beautiful hill") in the Quechua tongue, was discovered by Diego Gualpa, an Indian, in April, 1545. One story says he detected silver when his llama scratched the earth.

If Diego had known how much suffering his find was to bring to his people in the former kingdom of the Incas, he would surely have kept quiet. But five rich veins were located close to the surface, the mountain was renamed Cerro Rico and soon Potosí had 160,000 inmates, a colorful mixture of officials, traders, desperados, and millionaires, plus at least 800 professional gamblers and 120 prostitutes.

From its mines scattered an estimated 46,000 tons of silver, worth anything from US $ 5,000 million ups in modern terms. It brought undreamed-of wealth to a handful of adventurers, adorned churches and palaces, and helped pay for Spain's Great Armada and a series of wars. It also welcomed misery and death to thousands of Indians forced to work below ground.

In Potosí only the best was good enough for the silver barons. They competed in licentiousness and conspicuous consumption. They shipped their finery back to Paris to have it properly dry-cleaned while their ladies wore elegant shoes with heels of solid silver.

Today the city, declared by UNESCO a World Heritage site, is remote and sleepy and conditions underground are still perilously primitive, as I learned when a young student guided me through some of the 785 kilometers of tunnels honeycombing Cerro Rico. Little silver comes out these days for the most accessible veins are exhausted.

Tin replaced it in importance, making fortunes for a lucky few. But, after the bottom fell out of the tin market in 1985, thousands of miners lost their jobs and only a few mines struggle on.

The dream of easy wealth contributed to Spain's stagnation, helping to impoverish it for centuries. The riches of the Indies were frittered away – and that perhaps is the revenge of Potosí.

Those who carried off its treasure were left with nothing either. Except memories of the silver rush, inshrined in a popular Spanish phrase: "Vale un potosí! It's worth a king's ransom!"